Abstract
After 1958, when scientific satellites began exploring the Earth magnetic environment, many puzzling phenomena could be directly examined, especially the polar aurora and disturbances of the Earth's magnetic field [see Stern, 1989a]. The notion of the solar wind, introduced that same year, helped clarify the role of the Sun in driving such phenomena. The large-scale structure of the magnetosphere, the space region dominated by the Earth's magnetic field, was gradually revealed within the next decade: its trapped particles, its boundary, and its long magnetic tail on the night side. Inevitably, however, the new discoveries led to new questions at a more fundamental level, about the transfer of energy, the flow patterns of plasmas and electric currents, the acceleration of the aurora, and about transient events such as magnetic substorms and storms, which energized ions and electrons. Though significant progress has occured in some of these areas, many unresolved issues still remain. This review outlines the history of magnetospheric research, draws some general conclusions and provides an extensive bibliography.

Clicking on any marked section on the list below brings up a file containing it and all unmarked sections immediately following it on the list. This list is repeated at the beginning of each file.

1. Introduction
2. Discovery of the Radiation Belts
3. Artificial Belts and Early Studies
4. The Large Scale Structure
5. Convection
6. Reconnection
7. The Open Magnetosphere
8. Observational Tests
9. The Polar Aurora
10. Field Aligned Voltage Drops
11. Birkeland Currents
12. Substorms: Early Observations
13. Substorms: The Satellite Era
14. Substorms: Theory
15. Convection in the Geotail
16. Planetary Magnetospheres
17. Other Areas
18. Assessment

1. Introduction

This is the second part of a concise history of observations of the Earth's magnetosphere and of their interpretation. It and the first part [Stern, 1989a, henceforth denoted BH-1] are meant to help trace the development of magnetospheric physics in a unified context and to outline its framework of observations and ideas. The early years, around 1957-64, are covered chronologically, after which the coverage is arranged by topics--convection, reconnection, aurora, Birkeland currents and substorms. At the end some overall trends are assessed, as well as the current state of the discipline. Readers who find this article too technical are referred to an exposition on the world-wide web by Stern and Peredo [1995].

This brief account is based primarily on work published in English, which covers US efforts fairly completely but is unfortunately far less detailed on space research in the USSR and elsewhere. The first part (BH-1) covered earthbound studies of the magnetosphere before artificial satellites were available, and here the rest of the story is presented. The concluding section contains an assessment of overall trends as well as of the current state of the discipline.

This account is mainly based on published source, rather than on personal papers or interviews. It must therefore be viewed as a mere framework, in which many details remain to be filled.

As early as 1942 cosmic ray detectors observed the arrival of high-energy ions associated with solar activity, reaching at times up to approximately 10 GeV [Forbush, 1946; Pomerantz, 1984; Van Allen, 1993]. For many years such events were credited to solar flares, although recent evidence points to a much better correlation with coronal mass ejections [Gosling, 1993]; their most plausible energy source, then as now, seems to be the intense magnetic field of sunspots. It was speculated that somehow part of that field was "annihilated" by a rapid process and its energy used to accelerate ions and electrons, the latter revealed indirectly by intense bursts of radio noise, and more recently, by X-rays.

The process most favored for such energy release was magnetic merging or magnetic reconnection (synonymous terms). It may be loosely defined as a flow of plasma in which some of the field lines threading the plasma pass through a neutral point or neutral line at which the magnetic field vanishes. The idea originated with Giovanelli [1947; Hones, 1984b] and was then developed by Sweet [1958] and especially by Dungey [1953, 1963, 1994, 1995; Stern, 1986].

Figure 6

The starting point is the observation that the field-line sharing property associated with equation (1) can be violated if plasma flows through a neutral point (Figure 6) where B=0 and where the field's direction is undetermined. In the X-type neutral point drawn here (actually a neutral line if this configuration extends unchanged into the third dimension) field lines cross in the pattern of the letter X and plasma arriving on field lines of the regions "1" and "2" depart on differently connected lines in "3" and "4". Dungey, Sweet and others proposed that this process might somehow modify the large-scale magnetic configuration and thereby release magnetic energy. Particles would be accelerated by the electric field associated with the motion, producing fast jets of plasma flowing away from the neutral line as the plasma exits on lines "3" and "4", and shocks which heat the plasma [Levy et al., 1964].

Additional effects must be invoked, for by (1), if E is finite and B tends to 0, the velocity v which particles need to keep up their field-line sharing property becomes infinite. Sweet [1950] showed that in conducting fluids with finite resistivity the plasma's motion lags behind that of field lines, and therefore reconnection theories have often assumed a finite (but small) resistivity in the region near B=0. Other processes which preclude an infinite v may also play a role, e.g. ion or electron inertia [Vasyliunas, 1975, table 2].

A somewhat different type of process ("group 2 merging" of Vasyliunas, [1975], p. 307) is illustrated by the collision of two bodies of plasma permeated by magnetic fields of equal intensity but opposing directions, separated by a "neutral sheet" of zero field intensity. The plasma may emerges as a narrow stream along the sheet, perpendicular to field lines, its magnetic field "annihilated" and its particles accelerated by the attendant E, though its electric neutrality may pose problems [Stern, 1990].

Magnetic reconnection is relevant to magnetospheric physics in two distinct ways: it makes possible a realignment of field line connections, e.g. the establishment of a linkage between the Earth's field and the IMF, and it may also release magnetic energy and accelerate particles. The first aspect is important to the concept of the open magnetosphere, the second to substorms, two items discussed separately further below.

As noted earlier, many researchers arrived at magnetospheric physics from the study of solar energetic particles, and they brought with them an interest in reconnection [Parker, 1963]. That led to a 1963 symposium at Goddard Space Flight Center [Hess, 1964] where, among other things, the theory of Petschek [1964, 1995] was presented, giving a more detailed scenario of the reconnection process. Important references to later work may be found in a comprehensive review by Vasyliunas [1975], in the proceedings of a 1984 conference at Los Alamos [Hones, 1984a] and in reviews by Sonnerup [1979] and by Forbes and Priest [1987]. Avenues explored nowadays include the relation to tearing instabilities in plasmas [Schindler and Birn, 1978], reconnection at multiple points [Lee and Fu, 1985] and relations to chaotic field line topology [Hesse and Schindler, 1988]. A growing number of studies simulate reconnection by means of fast computers.

There exists some evidence for reconnection from direct observations at the dayside magnetopause [e.g., Paschmann et al., 1979; Sonnerup et al., 1981] but it is difficult to verify details of the mechanism. In regions where reconnection seems likely to occur, magnetic fields are quite variable and with isolated spacecraft it is almost impossible to extract their structure. The existence of a rarefied "depletion layer" outside the magnetopause, seen only when the directions of B inside and outside are similar, is taken as evidence for reconnection. Claims have also been made that characteristic oscillations of the magnetic field observed near the dayside magnetopause, associated with southward IMF and termed "flux transfer events" [Russell and Elphic, 1978, 1979; Elphic, 1994], are local signatures of "patchy reconnection", but in spite of extensive studies, such events remain poorly understood.

7. The Open Magnetosphere

Reconnection was first applied to magnetospheric physics by Dungey [1961], as the key ingredient of his alternative theory of convection. Dungey proposed that an X-type neutral point (or line) at the front of the magnetosphere enabled terrestrial field lines to link up with interplanetary ones and produce "open" field lines, with one end on earth and the other in distant space.

Figure 7

Figure 7 (from Hill [1983]) gives Dungey's original scenario, which assumed a purely southward directed interplanetary magnetic field (IMF). Lines 1 and 1' merge at a sunward X-type point (mp marks part of the magnetopause) to produce open lines 2 and 2', carried tailward by the solar wind in which they are embedded, to positions such as 3 and 3'. Ultimately these field lines reconnect at a distant neutral point in the tail, to produce an interplanetary field line 4 which is carried away by the solar wind, and a "closed" line 4' attached to Earth at both ends, which then flows sunward in the third dimension until it becomes the closed field line 1' which reconnects with 1. It is often held that these points are broadened to neutral lines of finite length in the direction perpendicular to the drawing, to accomodate the finite rate of flux reconnection.

The polar convection pattern and the polar electric field resulting from this motion qualitatively resemble those expected from the viscous-like drag proposed by Axford and Hines, The magnetopause now is no longer a surface containing field lines, but instead is often identified with an observed sharp discontinuity in the magnetic field, interpreted theoretically as a shock transition related to magnetic reconnection. It will have a normal magnetic component Bn which, by all predictions, is quite small (about 0.5-1 nT), making it difficult to confirm or refute this scenario by in-situ magnetic observations.

Figure 8

Reconnection at N1 probably imparts little energy to the plasma. Its real significance is the creation of "open" field lines such as 2 and 2', linked to both the solar wind and the ionosphere. Because electric currents in a plasma flow easily along field lines, such lines can form a dynamo circuit, a closed circuit part of which traverses a medium moving relative to the rest. A circuit of this kind (ABCD in Figure 8) can drive an electric current and produce an electric field in the polar ionosphere: its energy is obtained by slowing down the moving solar wind or mantle plasma threaded by it, and much of that energy is then deposited as ohmic heat in the ionospheric part of the circuit.

Note that the currents in this circuit (in both polar caps) flow earthward on the morning side of the pole (AB) and away from Earth on the evening side (CD), which is also the pattern of region 1 Birkeland currents (below). If the tail current follows the "theta pattern" of Axford et al. [1965; Dessler and Juday, 1965], the circuit EFGH may also be viewed as a dynamo, supplying energy that heats the plasma sheet.

8. Observational Tests

Dungey's process is expected to operate best if the IMF is purely southward, for then the IMF direction matches that of the Earth's polar field lines which link up with it (Figure 9a). If the Bz component of the IMF is southward (negative) but additional components also exist, the situation is known as "southward IMF": the linkage is still relatively easy, but interplanetary field lines must bend somewhat to make the connection (Figure 9b). The bending becomes severe if Bz > 0 ("northward IMF"), because interplanetary field lines then start out headed for the "wrong" pole (Figure 9c).

Figure 9

A major boost for Dungey's ideas was the discovery [Fairfield, 1966, 1967] that the level of magnetospheric "storminess" and of energy transfer from the solar wind to the magnetosphere depended strongly on IMF Bz. During southward IMF substorms are more frequent, the polar caps (assumed to contain open field lines) are fairly large and display a well-defined 2-cell convection pattern, and auroral ("Birkeland") currents (further below) are steady and strong. At times of northward IMF the magnetosphere is much quieter, the polar caps shrink and their E weakens. The effect is asymmetrical: when Bz is southward, increases in its magnitudes are correlated with increased activity, but the magnitude of a northward Bz seems to matter little [Burton et al., 1975]. A strong dependence of magnetospheric behavior on IMF Bz was later demonstrated by numerical simulations of the magnetosphere, conducted on fast computers and based on the MHD equations [e.g., Walker et al., 1993].

The Svalgaard effect [Svalgaard, 1968, 1972, 1973; Mansurov, 1969; Wilcox, 1972] is another interesting piece of evidence for a linkage between the IMF and terrestrial field lines. That is an asymmetry in the daily variation in polar regions, correlated with the interplanetary By component.

Owing to the interplay between solar wind outflow and the Sun's rotation, IMF field lines near Earth tend to lie close to the (x,y) plane, with B in the (x,-y) and (-x,y) quadrants and making an angle of about 450 with the x-axis, as predicted by Parker. Such lines can have one of two polarities--away from the Sun or towards it, corresponding to positive or negative By. Wilcox and Ness [1965; Wilcox, 1972] studied the prevalence of such polarities and showed that they tended to persist over times of a week or two, suggesting that the IMF in the plane of the ecliptic formed large-scale "sectors" of outward-pointing or inward-pointing field lines, co-rotating with the Sun. Often only two sectors exist, but at times they are more numerous, depending on the distribution of magnetic field sources on the Sun.

In 1926 K. Lassen established a magnetic observatory on Greenland which among other things observed the local daily magnetic variation. Around 1968 Svalgaard noted that the variation on quiet days could be classified as belonging to one of two patterns, and Wilcox suspected these correlated with interplanetary sectors. A large "blind" test was conducted [Friis-Christensen et al., 1971] and it confirmed the effect. The phenomenon might be connected with the By-related asymmetry in the pattern of polar E, later found by Heppner [1972b] ; it would be hard to explain, if terrestrial field lines had no link to the IMF.

Another observation suggesting the existence of "open" field lines is the asymmetric access to the polar caps of the high-energy tail ("strahl") of solar wind electrons (» 0.5 keV), producing the "polar rain" precipitation. Depending on the IMF sector in which the Earth is immersed, that "rain" is much more intense in the polar cap whose magnetic polarity allows direct connection to the Sun [Yaeger and Frank, 1976].

Problems in observing merging near N1 were already described. The distant nightside neutral line N2 has never been clearly identified: its signature should be a reversal of Bz from northward (Bz>0) to southward (Bz<0). Around 1983, when ISEE-3 probed the distant tail, it observed that periods of Bz<0 became more frequent at distances greater than approximately130 RE [Slavin et al., 1985], but that was only a statistical average of a rather variable quantity.

ISEE-3 has also shown [Slavin et al., 1985] and Geotail has confirmed, that in the distant tail past about 100 RE , plasma flowed tailwards at velocities that tended to increase with distance, up to where they about matched the velocity of the solar wind. This might be due to viscous transfer of plasma and momentum, but could also be the result of reconnection.

Following a great auroral display in Connecticut, on July 1, 1837, E.C. Herrick [1838, cited by Siscoe, 1980] wrote (italics in the original):

"It is worthy of notice that on this occasion there were two well marked and distinct seasons of greatest brilliance or fits of maximum intensity, at intervals of about four hours. It will be found on examination of former accounts, that this is a common feature of Auroral exhibitions of unusual brilliance."

Birkeland's polar storms are now known as (magnetic or magnetospheric) substorms. These violent twitches of the Earth's magnetic tail energize ions and electrons, inject some of them into the ring current, and greatly increase the rate at which energy is released in the magnetosphere. Indeed, many parallels exist between substorms and impulsive particle acceleration events on the Sun, and both are believed to be powered by the conversion of magnetic field energy. For all these reasons the substorm may be the most interesting problem in magnetospheric physics and a great challenge to both observer and theorist.

As noted in BH-1, Birkeland's ideas were opposed by Sidney Chapman [Chapman and Bartels, 1940; Fukushima, 1994, sect. 6]. Chapman contrasted the short time scale of polar disturbances with the much longer one of global magnetic storms and proposed that "polar storms" were merely phases of the global storm. Around the middle of the century such events were called "magnetic bays" because on a magnetogram (the plotted output of a magnetic observatory) they resembled bays on a coastline (according to Chapman and Bartels [1940], this term is due to Chree [1911,1912]). A study of bays was conducted by Silsbee and Vestine [1942; also Fig. 2 , Stern, 1977] who deduced a 2-cell pattern with strong electrojets near the boundary of the polar cap.

While Birkeland believed that auroral currents originated in distant space, the consensus in mid-century was that they resembled the well-known diurnal magnetic variation whose currents were attributed to tidal dynamo effects in the ionosphere, and that they were completely contained inside the ionosphere [Vestine and Chapman, 1938]. It was thought that the large polar magnetic variations arose by a similar process, but were much more intense because ionospheric conductivity was enhanced in regions bombarded by the aurora. Thus Harang [1951; p. 94] wrote, after explaining the tidal dynamo:

"The intrusion of electrically charged particles which produce the aurorae, strongly increases the ionisation and thus the conductivity of the ionised layers. Besides this, one must also assume secondary effects, such as expansion or heating of the upper atmosphere, which may increase the movements of the layers along the auroral zone. The polar storms are therefore, according to these views, due to an increase in the conductivity and velocity of movements of the upper layers."

The word "substorm" first appeared in Chapman's writings in 1961 [Akasofu and Chapman, 1961, p. 1339], referring to a bay-like disturbance assumed to be a phase of the global magnetic storm. Two years later Akasofu and Chapman [1963] compared the signatures of magnetic storms near the equator and in the auroral zone (Figure 14). Near the equator the magnetic field variation was simple and familiar, a gradual weakening of the field on a typical time scale of 6 hours, followed by a slow recovery. In the auroral zone, on the other hand, the magnetic record was punctuated by many short but intense magnetic bays, which the authors again named substorms.

Figure 14

13. Substorms: the Satellite Era

The International Geophysical Year (IGY) 1957-8 (actually extended to a year and a half) brought not only the first scientific satellites but also a great expansion in auroral observations and widespread use of "all-sky cameras" [see Eather, 1980] which photographed the entire sky as reflected in a convex mirror. Using such records, Akasofu noted in 1964 that magnetic bays, which also occurred widely outside magnetic storms, were associated with a distinct pattern of auroral intensification and expansion, and proposed to name the phenomenon "auroral activation" [Akasofu, 1970]. Chapman however insisted on "auroral substorm" and that was the name used in the article's title [Akasofu, 1964]. Later Akasofu favored "magnetospheric substorm" [Akasofu, 1977; Siscoe, 1980], while Rostoker [1972a has used "polar magnetic substorm"; the commonly used term nowadays is "magnetic substorm" or simply "substorm." Today's view is that the "substorms" which Chapman identified inside magnetic storms are of a similar nature, except perhaps bigger and more frequent, capable of injecting appreciable numbers of ions and electrons into long-lived orbits of the ring current region [Lui et al., 1987].

During 1964-6 Akasofu and his group studied the morphology of substorms in great detail [Akasofu et al., 1964, 1965a,b,c; 1966a,b,c,d; Akasofu, 1966]. Their "classical" substorm phases (individual storms may vary) are still accepted: an initial brightening of a quiet arc, the expansion of the aurora polewards (either by the motion of existing arcs or by formation of new ones), a westward surge along the auroral oval, gradual breaking-up of arcs and final recovery.

A deeper understanding was gained after about 1965, when satellites began observing the great changes accompanying substorms in the Earth's magnetic tail. They observed magnetic field lines becoming stretched prior to substorm onset (Figure 15, from Fairfield and Ness [1970]) and then rebounding to more dipole-like shapes ("dipolarizing"). This was also noted by Heppner [1967] who wrote (p. 184): "The view that is favored is that the tail field is partially collapsing back towards a less stressed condition during a negative bay."

Figure 15

The preliminary stretching may be observed as close as synchronous orbit, at 6.6 RE [e.g., Baker et al., 1981] and may begin as long as one hour before substorm onset: the prevalent idea (originally widely debated) is that this is the "growth phase" during which magnetic energy is stored [McPherron, 1970, 1972], and often an analogy is drawn between the stretching of field lines in this phase and the stretching of a slingshot. When the field lines rebound, the stored energy goes to accelerate particles and to drive currents. A large increase in the flux of ions and electrons is then observed at the nightside near the inner edge of the cross-tail current, e.g. in the synchronous orbit at 6.6 RE [De Forest and McIlwain, 1971], but what exactly goes on is still not understood [Mauk and Meng, 1987]. Typical injected energies are 1-10 keV, but particles up to 100 keV and more have also been observed [Nagai et al., 1983].

Satellites in the plasma sheet may observe disappearances ("drop-outs") of the plasma at the time of onset, and after onset a satellite which had been outside the plasma sheet may be suddenly engulfed by it. Early observations of such changes [Hones et al., 1967, 1970; Hones, 1979] were complicated by the fact that they were performed by "piggyback" instruments aboard the Vela satellites which carried no magnetometers, since their primary mission was to detect violations of the ban on nuclear tests in space. The ultimate explanation was that the plasma disappeared when the plasma sheet was severely stretched and became extremly thin, while the sudden appearances of plasma were associated with dipolarization, when plasma energized by the substorm rebounded earthward, swelled field lines of the near-earth tail and extended the plasma sheet past the satellite.

The deep magnetic bays accompanying the substorm arise from greatly enhanced electrojets, and the AE index [Sugiura and Davis, 1966] is often taken as a gauge of the level of substorm activity. Observations have suggested [McPherron et al., 1973, Fig. 7-8] that during substorms Birkeland currents are reinforced on the nightside by a system with region 1 polarity, arising from a diversion of part of the cross-tail current through the ionosphere. Because the shape of the diversion circuit tapers towards the Earth, this is known as the "substorm wedge current". In the ionosphere the wedge current follows the auroral oval, whose conductivity is greatly increased by the aurora, and thus reinforces the westward electroject around midnight. The wedge current may be intense enough for its magnetic effects to be observed at middle latitudes [Clauer and McPherron, 1974a, b] as well as in synchronous orbit [McPherron and Barfield, 1980].

By 1972 most observational features of the substorm had been identified, and they were reviewed by Rostoker [1972a] who also summed up the history of substorms (p. 163, 200), and by Aubry [1972]. A conference on substorms was held in October 1972 [Vasyliunas and Wolf, 1973] and an initial coordinated study of the substorms of 15 August 1973 was undertaken. The results of that study appeared in 1973 in 9 consecutive articles (J. Geophys. Res., 78, p. 3044-3149) the last of which [McPherron et al., 1973] presented an interpretation which included the "wedge circuit."

14. Substorms: Theory

As the features of substorms became known, attempts were made to explain them. One important feature was the strong correlation between substorms and "southward IMF". If the magnetosphere was quiet during a spell of northward IMF Bz, and suddenly Bz turned southward and stayed that way, it was found that a high probability existed for a substorm to erupt within an hour or so.

A further link was provided by Aubry et al. [1970; Aubry and McPherron, 1971] who found evidence that, other things being equal, the "nose" of the magnetosphere was pushed in closer to Earth at times of southward IMF Bz, a phenomenon qualitatively evaluated by Holzer and Slavin [1978] and by Sibeck et al. [1991; Roelof and Sibeck, 1993]. Aubry termed this phenomenon "erosion" of the magnetopause and claimed it occurred because closed field lines were being reconnected to interplanetary ones near N1 (Figure 7) faster than closed lines were arriving from the tail to take their place.

Coroniti and Kennel [1972] explored later developments of this scenario. If magnetic flux is removed from N1 faster than the sunward flow initiated near N2 brings it back, additional flux will pile up in the tail lobes. The lobes then swell and present a larger obstacle to the solar wind, which therefore compresses them more, increasing the lobe field BL: they identified this process with the growth phase of substorms, noting that the magnetic energy in the tail, whose density is proportional to BL squared, would increase.

Figure 16

Ultimately, in this scenario, the increased southward IMF reaches N2 and increases the rate of reconnection there, and after a while the supply of returning magnetic flux reaching N1 again matches the demand. But meanwhile other processes may intervene. The increased pressure on the lobe may squeeze the plasma sheet, causing reconnection at an internal neutral line N3 (Figure 16), so that the flux returning sunward is now supplied by reconnection at N3. Tailward of N3 an isolated magnetic bubble will be created, named "plasmoid" by Hones [1976; p. 567], a term previously applied by Bostick [1956, 1957, 1986] to a type of transient plasma bubble observed in the laboratory. Hones [1979, p. 393] described it as "...a blob of magnetospheric plasma ... detached from the magnetotail plasma...". The reconnection process at N3 was assumed to provide the substorm's energy and to accelerate particles; observations of impulsively accelerated particles in the tail [e.g. Keath et al., 1976; Roelof et al., 1976] were believed to indicate proximity to to N3.

The preceding scenario, with various modifications, has dominated the community's view of substorms in the last 20 years. In particular, Hones [1979] has collected evidence in its favor, and has argued that once a new neutral line N3 was formed, the tailward motion of the plasmoid would stretch it into a neutral sheet, explaining the formation of a very thin section of the plasma sheet ("thinning") inferred from the observed disappearance of plasma. This was disputed by Frank et al. [1976] who claimed substorms originated in "fireballs", possibly associated with boundary layers. The controversy persisted for a while [Hones, 1977, 1978a, b, c; Frank and Ackerson, 1977; Frank et al., 1978a, b], with Hones claiming that Frank's examples were in fact ordinary reconnection events, but it ultimately died down when no alternative scenario based on fireballs emerged.

Since that time several alternative theories of the substorm have been proposed [Kan, 1990]. Most interpretations place N3 fairly close to Earth (about 15 RE), but some views [Rostoker and Eastman, 1987] argued that substorms may reflect enhanced reconnection (and other processes?) at N2. Alternative theories have invoked a "thermal catastrophe" [Goertz and Smith, 1989], Alfven waves bouncing between the ionosphere and the tail [Kan et al., 1988] and disruption of the cross-tail current [advocated by Lui, 1991]. The proliferation of models has led to some skepticism [Stern, 1989b], and a meeting was held in Victoria, B.C. to seek some general agreement [Rostoker et al., 1980], but it did not clarify much.

One approach to studying substorms is to try correlate their variations with interplanetary stimuli, and thus seek to identify their causes or "triggers." Part of the problem here is the gauging of a substorm's intensity, and many studies have used for this the auroral AE index, or the related AU and AL indices. These reflect the strength of the auroral electrojets and therefore of the Birkeland current system, and they are known to become very high during large substorms.

Coroniti and Kennel [1972], Hones [1979] and most other researchers argued that the substorm obtained its energy from magnetic energy stored in the tail lobes, accumulated during a "growth phase" preceding substorm onset, during which the tail's magnetic flux increased [Caan et al., 1975]. Perreault and Akasofu [1978], however, found good correlation of AE with an "epsilon-parameter," constructed from solar wind characteristics and very sensitive to IMF Bz. They therefore proposed that substorms represented periods of stronger coupling between the solar wind and the magnetosphere, enabling the latter to extract more energy, and were thus "driven" by interplanetary conditions rather than representing the "unloading" of stored energy [Akasofu, 1980]. Some physicists now claim that both "unloading" and "driven" processes are involved. Predictive linear filters have also been used to study the way the solar wind input relates to AE [Iyemori et al., 1979; Clauer et al., 1981].

Theorists who support the "near-earth neutral line" (NENL) scenario have sought the "trigger" mechanism which initiates the onset of substorms, possibly some plasma instability. Computer simulations based on idealized MHD equations and assuming (purely) southward IMF [e.g., Walker et al., 1993] have supported the NENL scenario, yielding (with southward IMF) even more pronounced reconnection than seems to be observed.

15. Convection in the geotail

An interesting idea about the origin of substorms was proposed by Erickson and Wolf [1980; Hau et al., 1989; Erickson, 1984, 1992]. In the ideal MHD approximation, in the absence of rapid accelerations, it is expected that the magnetosphere is always close to force balance, mainly between pressure gradients and the magnetic force:

Properly p is a tensor, but in the plasma sheet the observed distribution of ions is close to isotropic and hence a scalar p is often used there. Solutions of (2) appropriate to a realistic 3-dimensional magnetosphere are not known, but two-dimensional solutions for a scalar p, assuming a linear dipole that extends indefinitely in the y-direction, can be obtained (at least numerically) from the Grad-Shafranov equation [e.g. Voigt and Wolf, 1988].

Erickson and Wolf [1980] noted that the existence of a convective plasma flow in the tail imposes additional restrictions. If the tail's field lines move with the flowing plasma, either the magnetic pattern is static and satisfies (2), and then the convection is such that each field line of the pattern is carried into another one; or else the pattern evolves, in which case (2) must hold at each intermediate stage. Erickson and Wolf showed that observed patterns of B and expected patterns of E were not compatible with a static scenario.

Erickson [1992] later simulated the field's evolution on a computer, satisfying (2) at all times; his calculation was two-dimensional, but flux arriving near Earth was allowed to "escape sideways" rather than piling up. This process led to a very weak B near the earthward edge of the plasma sheet (x near -12 RE), suggesting in almost all cases the imminent formation of a near-earth neutral line (the simulation could not go far enough to confirm it). By this scenario, substorm-type events may be an inevitable outcome of convection in the tail.

Attempts to actually observe this convection raise new problems. The double-probe method for observing E in low Earth orbit fails in the rarefied plasma of the tail, but the plasma's bulk flow can be inferred by measuring ion flux anisotropies. The first attempt [Frank and Ackerson, 1979] suggested a great deal of back-and-forth sloshing of plasma, but no underlying persistent earthward motion. A later study by Huang and Frank [1986] filtered out plasma sheet boundary layer observations, which contained field-aligned flows, and obtained an average earthward flow in the plasma sheet (r < 22 RE) of about 20 km/s, much below the expected rate. Recent studies by Angelopoulos et al. [1992] suggest that high-speed earthward plasma flows do exist (at about 150 km/s) but only about 7% of the time. The problem is thus still unsolved.

Space missions to othe planets of the solar system have shown that most of them are magnetized. In particular, the giant planets are magnetized much more strongly than Earth [Bagenal, 1992] and their magnetospheres are all much larger than ours, in part because of the stronger dipole moments, in part because the solar wind becomes increasingly rarefied far from the Sun. Tiny Mercury has a magnetic moment only about 1/2000 that of Earth and a very small magnetosphere, Venus seems non-magnetic and Mars may or may not have a weak field. The magnitudes of the dipole moments of Mercury, Earth, Jupiter, Saturn, Uranus and Neptune, in units of 10^25 Gauss-cm3, are 0.004 (approx.), 7.9, 150,000, 4300, 420 and 200, respectively [Lepping, 1995].

The most striking thing about these magnetospheres is their great diversity and this brief overview cannot possibly do justice to the extensive research done on them. Good accounts of the initial observations and of many associated discoveries can be found in special sections of the journal Science [1974, 1975a, 1975b, 1979a, 1979b, 1980, 1981, 1982, 1986, 1989, 1992], published soon after the planetary encounters by Pioneer 10 (Jupiter), Mariner 10 (Mercury), Pioneer 11 and Voyager 1 (Jupiter and Saturn), Voyager 2 (Jupiter, Saturn, Uranus and Neptune) and Ulysses (Jupiter). The Galileo spacecraft reached Jupiter in December 1995 and entered an orbit around the planet, after successfully launching a probe into Jupiter's atmosphere.

The strongest magnetic field and the most intense trapped radiation are found in the magnetosphere of Jupiter, which is also the largest [Dessler, 1983]. This was furthermore the first planetary magnetosphere to be discovered: in 1955 strange radio noise was traced by Burke and Franklin to the planet Jupiter [Franklin, 1959, 1985], although it was only attributed to magnetically trapped plasma after the discovery of the Earth's radiation belt [Drake, 1985].

Jupiter's magnetosphere is loaded with ions of sulfur and also of sodium, ejected from "volcanoes" on the satellite Io. Io also has an ionosphere with an interesting dynamo interaction with Jupiter [Ness et al., 1979]. Jupiter's trapped plasma carries a dense ring current, and seems to co-rotate with the planet, perhaps up to the magnetopause. Its density profile contains dips due to absorption by Jupiter's moons and by the planet's thin ring, which resembles Saturn's ring but is much narrower; the existence of that ring was first suggested by an absorption feature in the belt [Acuna and Ness, 1976]. Jupiter also has an aurora, observable from Earth, and radio emissions with complicated patterns, some of them correlated with the position of Io.

Saturn's magntosphere similarly tends to rotate with the planet and contains absorption features. The planet seems to have an inner belt like the Earth's, believed to arise from albedo neutrons knocked out of the planet's rings by cosmic rays [Cooper and Simpson, 1980].

The Earth's magnetic axis is very close to its rotation axis. Similar proximity between the two axes was found for Jupiter, Saturn and Mercury (for Saturn the axes coincided within observational error), and this was therefore widely held to be a general feature of planetary magnetic fields. At the time of the encounter between Voyager 2 and Uranus, on 24 January 1986, the planet's axis pointed within a few degrees of the Sun. It was therefore expected that here was a "pole-on" magnetosphere, a previously unstudied configuration in which the axis of the planetary magnet pointed approximately into the solar wind.

But it was not to be. The magnetic axis of Uranus--and later also that of Neptune--was found to make an angle of about 60 degrees with the planetary rotation axis, causing the field to swing widely with each rotation of the planet. As Uranus orbits the Sun, there will arise occasions when a "pole-on" magnetosphere is (briefly!) realized, but it did not happen during the Voyager 2 encounter.

Finally, Mercury's magnetosphere [Ness, 1979] seems to be too small for energetic particles to become trapped in it. However, as Mariner 10 went past the planet's night side, it encountered a burst of energetic particles, which could be the result of a substorm-type event in Marcury's magnetic tail.

Interesting magnetic cavities are also formed around Venus, the Moon and comets (and probably, Mars), but if the obstacle is not a planetary magnetic field, the cavity produced is quite different from the ones described above. All this suggests a rather rich field for future research, involving configurations unlike the Earth's, on which many additional observations still remain to be made.

17. Other Areas A brief overview like this one must by necessity omit many important topics, such as:

(1) Instrumentation:

e.g. magnetometers [Heppner, 1963; Ness, 1970], electric field probes [Fahleson, 1967; Cauffman and Gurnett, 1972]; charged particle detectors and mass spectrometers. A sampling of articles or collection of articles (only first paper cited) on specific spacecraft and their instruments includes Injun 3 [O'Brien et al., 1964], the OGO series [Ludwig, 1963; Bostrom and Ludwig, 1966], Atmosphere Explorer 1 [Dalgarno et al., 1973], S3 or Explorer 45 [Longanecker and Hoffman, 1973], International Sun-Earth Explorer (ISEE) 1 and 2 [Ogilvie et al., 1978], Active Magnetospheric Particle Tracer Experiment (AMPTE) [Acuna et al., 1985] and Dynamics Explorer (DE) 1 and 2 [Hoffman et al., 1981]

(2) Wave phenomena in the magnetosphere:

[Shawhan, 1979], including whistlers [Helliwell, 1965; Al'pert, 1980; see also BH-1], auroral kilometric radiation [Gurnett, 1974], micropulsations [Hughes, 1983; Lanzerotti and Southwood 1979], 3/2 cyclotron frequency emissions, auroral hiss and other modes.

(3) The bow shock of the Earth:

[Dobrowolny and Formisano, 1973; Greenstadt and Fredricks, 1979; Kennel et al., 1985; Kennel, 1987].

18. Assessment

The preceding brief history only covers scientific aspects of magnetospheric physics. In addition, magnetospheric physics also has institutional, personal and social aspects.

An institutional history traces the evolution of the field and its accomplishments in the framework of the organizations which led it, of institutions, committees, executive decisions and of the individuals involved in them [e.g. Ezell, 1988]. An instructive example is "Beyond the Atmosphere" [Newell, 1980], an account of NASA's effort in space science 1958-1975 by a former NASA Associate Administrator who led those efforts for many years. It covers all fields, not just magnetospheric physics, but where its subject overlaps this narrative, it often paints a strikingly different picture.

Personal histories are first-hand accounts by participants. At best they give an unequalled intimate view of the discovery process. At worst they are carefully filtered, and their writers also do not always have the necessary discrimination and writing skill. Such deficiencies would matter less if such accounts were plentiful enough to allow comparison and cross-checking: sadly, only very few exist, which makes them particularly valuable, and their coverage of the field is rather patchy [Van Allen, 1983a, 1990 ; Eather, 1980, chapt. 19; Frank, 1990; Gombosi et al., 1994].

The community of magnetospheric physics has never been properly studied. It is relatively small: the membership of AGU's Section on Space Physics and Aeronomy stands around 3000 (1980--1604; 1985--1922; 1990--about 2600). This also includes scientists whose main interests are the upper atmosphere, interplanetary space and the Sun, but on the other hand may miss many workers outside the USA. As noted, this discipline arose from three main sources--plasma physics, work with rockets, balloons and ground instruments, and the study of cosmic rays. It began assuming its separate identity in 1959, when (led by James Van Allen) it chose the American Geophysical Union (AGU) as its home organization and the Journal of Geophysics Research (JGR) as its main means of communication.

Today that community is in a serious crisis, made evident, for instance, by a frustrating slow-down in the rate of discovery during the last decade 1984-1994. It may be instructive to speculate about the causes of this slow-down and its implications to the community's future.

One can roughly divide the record of magnetospheric physics in the space age into three periods: (1) the era of discovery, 1958-1965; (2) the expansion stage, 1965-1977; and (3) the era of stagnation, setting in gradually after 1977.

In the first period, the large-scale morphology was surveyed--particle populations, the main regions and the boundaries. In addition, this was the beginning of our ideas on convection and reconnection.

In the expansion stage, details were filled in--correlations with the IMF, substorm morphology, Birkeland currents, E//, auroral kilometric radiation, O+ ions in the ring current, ion beams and conics, injections at synchronous orbits, etc. Additional theoretical ideas were also introduced--the NENL theory of substorms, the Brice-Nishida theory, the Coroniti-Kennel theory, theories on the consequences of convection by Schield et al. and by Vasyliunas, and others not touched on here.

Since 1977 some observational details were added., e.g., about the magnetosphere with IMF Bz > 0, about the distant tail (by ISEE-3 and Geotail), the ring current (by AMPTE-CCE) and the plasma sheet (by ISEE 1-2 and AMPTE-IRM). Theories, too, have improved, but the main problems continue to elude us--the nature of substorms, structure of the open magnetopause, specifics of reconnection, convection in the tail, global structure during northward IMF and similar questions.

Why this apparent pause? Three possible reasons will be noted here: the nature of discovery, the choice of mission strategy and a missed transition in the evolution of magnetospheric physics.

(1) There exist two kinds of discovery in this field--discovery of new problems and discovery of solutions. The heady early period seemed packed with discoveries, but most of them belonged to the first kind. It was inevitable that satelites passing for the first time through the radiation belt, the magnetopause, cusp, bow shock or plasma sheet would make an important discovery; but while new phenomena accumulated, explanations of their features lagged, and they still do. In laboratory physics, when a new phenomenon is discovered, one can design experiments to focus on it; but magnetospheric physics, in common with the rest of geophysics, offers few controlled experiments and depends primarily on observations. Thus progress towards explanations is slow and uncertain.

(2) The cost of spacecraft is high, both in funds and efforts. All early space missions therefore involved isolated spacecraft, but it seems that the amount of information available from this mode is just about exhausted. Magnetospheric physics is synergistic: to understand global behavior, a coordinated network of satellites is needed.

After 1977 the field was ripe for such a network, but unfortunately the use of isolated spacecraft is still the norm. The Russian Interball (two spacecraft launched in 1995) and the European Cluster (due in 1996) each contain four coordinated spacecraft and promise to give valuable results, in particular in conjunction with the "Wind" and "Polar" spacecraft of the US. But a meaningful coverage demands a much larger number of platforms, as was made clear by CDAWs, Coordinated Data Analysis Workshops [e.g. Manka et al., 1982], which tried to analyze specific events and generally found that even with all available data, important questions could not be resolved.

(3) As noted, the magnetospheric community first assumed a separate identity around 1960. Independent space physics departments were established at selected universities--Iowa, UCLA, Rice, Alaska, then more--and space research groups were set up at NASA, Johns Hopkins Applied Physics Lab., Los Alamos etc. As the community expanded in 1965-77, it also began raising its first generation of internally-trained scientists.

But something seemed missing. A community needs not only its institutional identity but also a core of its accumulated knowledge, set up in an orderly way that can be passed on. Research and symposia lead to review talks and papers, which in turn lead to textbooks and courses, telling "such-and-such we are pretty sure of and can teach, this-or-that is unclear or controversial, and here are the boundaries of our knowledge."

Even now, rather little of this process of distillation has taken place, especially in observations: in substorm morphology, for instance, there is surprisingly little that can be regarded well-established. Possible reasons are too long and too controversial to list here, but the result has been a narrowness of scope and a lack of broad vision which even now hamper further progress and further planning.

This review is altogether too short to properly describe what such "core knowledge" may contain. Still, one hopes it will give its readers, especially younger members of the community, a uniform historical framework of the overall structure of their field.

Acknowledgments

A draft of this article was given for review to a large number of scientists involved in the discoveries described here, most of whom provided useful comments. The author thanks A. Dessler, J. Heppner, P. Hart, W. Hess, R. Hoffman, E. Hones Jr., G. Ludwig, M. Peredo, H. Petschek, J. Slavin, E. Smith, J. Van Allen, M. Walt and R. Wolf for their help in compiling this review, as well as two editors and three referees of the journal.

Note: Journals are cited by their most recent name; for instance, "Reviews of Geophysics" was "Reviews of Geophysics and Space Physics" in 1970-1984. The mark (c) indicates the first in a collection of articles.

Acuna, Mario H. and N.F. Ness

Summary of the initial results from the GSFC fluxgate magnetometer on Pioneer 11, in Jupiter, pp. 830-847, edited by T. Gehrels, U. of Arizona Press, 1976.

Acuna, Mario H., G.W. Ousley, T.W. McEntire, D.A. Bryant and G. Paschmann (c)

AMPTE mission, overview, IEEE Trans. Geoscience Electr., GE-23, 175-176, 1985

Aggson, Thomas L. and J.P. Heppner

"Probe measurements of electric fields in space", in Atmospheric Emissions, pp. 305-316, B.M.McCormac editor, Van Nostrand Reinhold, New York 1968.

Akasofu, Syun-Ichi

The development of the auroral substorm, Planet. Space Sci.,12, 273-282, 1964.

Akasofu, Syun-Ichi

The development of geomagnetic and auroral storms, J. Geomag. Geoelect., 18, 109-123, 1966.

Akasofu, Syun-Ichi

In memoriam Sydney Chapman, Space Science Reviews, 11, 599-606, 1970.

Akasofu, Syun-Ichi

Physics of Magnetospheric Substorms, xviii + 599 pp., D. Reidel, Dordrecht, 1977.

Akasofu, Syun-Ichi

The solar wind-magnetosphere energy coupling and magnetosphere disturbances, Planet. Space Sci., 28, 495-509, 1980.

Akasofu, Syun-Ichi and Sydney Chapman

The ring current, geomagnetic disturbance and the Van Allen radiation belts, J. Geophys. Res., 66, 1321-50, 1961.

Akasofu, Syun-Ichi and Sidney Chapman

The development of the main phase of magnetic storms, J. Geophys. Res., 68, 125-129, 1963.

Akasofu, Syun-Ichi, D.S. Kimball and Ching-I. Meng

The dynamics of the Aurora, I, Instabilities of the aurora, J. Atmos. Terr. Phys., 26, 205-211, 1964.

Akasofu, Syun-Ichi, Sidney Chapman and Ching.-I. Meng

The polar electrojet, J. Atmos. Terr. Phys., 27, 1275-1305, 1965a.

Akasofu, Syun-Ichi, D.S. Kimball and Ching-I. Meng

The dynamics of the Aurora, II, Westward traveling surges, J. Atmos. Terr. Phys., 27, 173-187 1965b.

Akasofu, Syun-Ichi, D.S. Kimball and Ching-I. Meng

The dynamics of the Aurora, III, Westward drifting loops, J. Atmos. Terr. Phys., 27, 189-196, 1965c.

Akasofu, Syun-Ichi, D.S. Kimball and Ching-I. Meng

Dynamics of the Aurora, IV, Polar magnetic substorms and westward traveling surges, J. Atmos. Terr. Phys., 28, 489-496, 1966a.

Akasofu, Syun-Ichi, D.S. Kimball and Ching-I. Meng

Dynamics of the Aurora, V, Poleward Motions, J. Atmos. Terr. Phys., 28, 497-503, 1966b.

Akasofu, Syun-Ichi, D.S. Kimball and Ching-I. Meng

Dynamics of the Aurora, VI, Formation of patches and their eastward motion, J. Atmos. Terr. Phys., 28, 505-511, 1966c.

Akasofu, Syun-Ichi, D.S. Kimball and Ching-I. Meng

Dynamics of the Aurora, VII, Equatorward motions and the multiplicity of auroral arcs, J. Atmos. Terr. Phys., 28, 627-635, 1966d.

Alfven, Hannes

A theory of magnetic storms and of the aurorae, K. Sven. Vetenskapakad., Handl., Ser. 3, 18(3), 1939. (Reprinted in part with comments by Alex Dessler and John Wilcox in Eos, 51, 180-194, 1970).

Alfven, Hannes

Cosmical Electrodynamics, Oxford University Press, 1950.

Alfven, Hannes and Carl-Gunne Falthammar

Cosmical Electrodynamics, Fundamental Principles, Oxford University Press, 1963.

Alpert, Yakov

40 years of Whistlers, J. Atmos. Terr. Phys., 42, 1-20, 1980.

Angelopoulos, Vassilis, W. Baumjohann, C.F. Kennel. F.V. Coroniti, M.G. Kivelson, R. Pellat, R.J. Walker, H. LŸhr and G. Paschmann

Bursty bulk flows in the inner central plasma sheet, J. Geophys. Res., 97, 4027-4039, 1992.

Atkinson, Gerald

Energy flow and closure of current systems in the magnetosphere, J. Geophys. Res., 83, 1089-1103, 1978.

Aubry, Michel P.

A short review of magnetospheric substorms,p. 357-364 in Earth Magnetospheric Processes, Billy McCormac, ed., D. Reidel, 1972.

Aubry, Michel P., C.T. Russell and M.G. Kivelson

Inward motion of the magnetopause before a substorm, J. Geophys. Res., 75, 7018-7031, 1970.

Aubry, Michel P. and Robert L. McPherron

Magnetotail changes in relation to the solar wind magnetic field and magnetospheric substorms, J. Geophys. Res., 76, 4381-4401, 1971.

Axford, W. Ian

The interaction between the solar wind and the Earth's magnetosphere, J. Geophys. Res., 67, 3791-3796, 1962.

Axford, W. Ian

Viscous interaction between the solar wind and the Earth's magnetosphere, Planet. Space Sci., 12, 45-53, 1964.

Axford, W. Ian

The good old days, J. Geophys. Res., 99, 19,199-212, 1994.

Axford, W.Ian and Colin O Hines

A unifying theory of high-latitude geophysical phenomena and geomagnetic storms, Canad. J. Phys., 39, 1433-1464, 1961. Reprinted with comments in The Upper Atmosphere in Motion, C.O. Hines and Colleagues, p. 933-967, AGU, Washington, DC 1974.

Axford, W. Ian, Harry E. Petschek and George L. Siscoe

Tail of the magnetosphere, J. Geophys. Res., 70, 1231-1236, 1965.

Bagenal, Fran

Giant Planet Magnetospheres, Ann. Rev. Earth. Sci., 20, 289-328, 1992.

Baker, Daniel N., E.W. Hones, Jr., P.R. Higbie, R.D. Belian and P. Stauning

Global properties of the magnetosphere during a substorm growth phase: A case study, J. Geophys. Res., 86, 8941-8956, 1981.

Barbier, Daniel

L'activitŽ aurorale aux basses latitudes, Ann. Geophys., 14, 334-355, 1958.

Birkeland, Kristian

The Norwegian Aurora Polaris Expedition 1902-3, A. Aschehoug, Christiania, Norway, 1908, 1913.

Bishop, Amasa S.

Project Sherwood--The US Program of Controlled Fusion, 216 pp., Addison-Wesley, 1958.

Blake, J. Bernard, W.A. Kolasinski, R.W. Fillius and E.G. Mullen

Injection of electrons and protons with energies of tens of MeV into L<3 on 24 March 1991, Geophys. Res. Lett., 19, 821-824, 1992.

Block, Lars P.

Potential double layers in the ionosphere, Cosm. Electrodyn., 3, 349-376, 1972.

Block, Lars P.

A double layer review, Astrophys. Space Sci., 55, 59-83, 1978.

Bostick, Winston H.

Experimental study of ionized matter projected across a magnetic field, Phys. Rev., 104, 292-299, 1956.

Bostick, Winston, H.

Experimental study of plasmoids, Phys. Rev., 106, 404-412, 1957.

Bostick, Winston H.

What laboratory-produced plasma structures can contribute to the understanding of cosmic structures both large and small, IEEE Trans. on Plasma Sci., PS-14, 703-717, 1986.

Bostrom, Carl O. and George H. Ludwig

Instrumentation for Space Physics, Physics Today, 19, no.7, 43-56, July 1966.

Bostrom, Rolf, A model of the auroral electrojets, J. Geophys Res., 69, 4983-4999, 1964.

Bostrom, Rolf

Currents in the ionosphere and magnetosphere, p. 445-458 in The Birkeland Symposium on Aurora and Magnetic Storms, A. Egeland and J. Holtet, editors, Centre de la Recherche Scientifique, Paris 1968.

Boyd, John S.

Rocket-borne measurements of auroral electrons, Rev. Geophys., 13, 735-740, 1975.

Brice, Neil M.

Bulk motion in the magnetosphere, J. Geophys. Res., 72, 5193-5211, 1967.

Brice, Neil M.

Differential Drift of Plasma Clouds in the Magnetosphere, unpublished manuscript, August 1973.

Brown, W.L., W.N. Hess and J.A. Van Allen

Introduction [to "Collected papers on the artificial radiation belt from the July 9, 1962, nuclear detonation], (c) J. Geophys Res., 68, 605-6, 1963.

Brush, Stephen G.

Prediction and theory evaluation: AlfvŽn on space plasma phenomena, Eos, 71, 19-33, January 9, 1990.

Burch, James L., S.A. Fields and R.A. Heelis

Polar cap electron acceleration regions, J. Geophys. Res., 84, 5863-5874, 1979.

Burke, William J. M.C. Kelley, R.C. Sagalyn, M. Smiddy and S.T. Lai

Polar cap electric field structure with northward interplanetary magnetic field, Geophys. Res. Let., 6, 21-24, 1979.

Burton, Rande K., R.L. McPherron and C.T. Russell

An empirical relationship between interplanetary conditions and Dst, J. Geophys. Res., 80, 4204-4214, 1975.

Bythrow, Peter F. , Thomas A. Potemra and Lawrence J. Zanetti

Variation of the auroral Birkeland current pattern associated with the north-south component of the IMF, p. 131-136 in Magnetospheric Currents, T.A. Potemra, ed., Amer. Geophys. Union, Washington, DC 1984.

Caan, Michael N, Robert L. McPherron and Christopher T. Russell

Substorm and interplanetary magnetic field effects on the geomagnetic tail lobes, J. Geophys. Res., 80, 191-194, 1975.

Cahill, Lawrence J., Jr.

Early study of the boundary of the geomagnetic field, in Physics of the Magnetopause, B.U.O.Sonnerup and P. Song, editors, p. 9-16, Amer. Geophys. Union, Washington, D.C. 1995.

Cahill, Lawrence J., Jr. and P.G. Amazeen

The boundary of the geomagnetic field, J. Geophys. Res., 68, 1835-1843, 1963.

Carovillano, Robert L. and George L. Siscoe

Energy and momentum theorems in magnetospheric physics, Rev. Geophys., 11, 289-353, 1973.

Carpenter, Donald L.

Whistler evidence of a "knee" in the magnetospheric ionization density profile, J. Geophys. Res., 68, 1675-1682, 1963.

Carpenter, Donald L. and C.G. Park

What ionospheric workers should know about the plasmapause-plasmasphere, Rev. Geophys., 11, 133-154, 1973.

Carruthers, George R., T. Page and R.R. Meier

Apollo 16 Lyman-alpha imagery of the hydrogen corona, J. Geophys. Res., 81, 1664-1672, 1976.

Cauffman, David P. and Donald A. Gurnett

Double-probe measurement of convection electric fields with the Injun 5 satellite, J. Geophys. Res., 76, 6014-6027, 1971.

Cauffman, David P. and Donald A. Gurnett

Satellite measurements of high latitude convection electric fields, Space Sci. Rev., 13, 369-410, 1972.

Chapman, Sidney and Julian Bartels

Geomagnetism, (2 vol.) 1049 pp.,Oxford Univ. Press, New York, 1940.

Chree, C.

Studies in Terrestrial Magnetism, 206 pp., McMillan & Co., London and New York, 1912 (also in Encyclopaedia Britannica, 11th ed. 1911, vol 17, pp. 353-385).

Chiu, Yam T. and M. Schulz

Self-consistent particle and parallel electrostatic field distributions in the magnetospheric-ionospheric auroral region, J. Geophys. Res., 83, 629-642, 1978.

Christofilos, Nicholas C. (c)

The Argus Experiment, J. Geophys. Res., 64, 869-876, 1959.

Clauer, C.Robert and Robert L. McPherron

Mapping the local time-universal time development of magnetospheric substorms using mid-latitude magnetic observations, J. Geophys. Res., 79, 2811-2820, 1974a.

Clauer, C.Robert and Robert L. McPherron

Variability of mid-latitude magnetic parameters used to characterize magnetospheric substorms, J. Geophys. Res., 79, 2898-2900, 1974b.

Clauer, C. Robert, R.L. McPherron, C. Searls and M.G. Kivelson

Solar wind control of auroral zone geomagnetic activity, Geophys. Res. lett., 8, 915-918, 1981.

Cooper, John F. and J.A. Simpson

Sources of high-energy protons in Saturn's magnetosphere, J. Geophys. Res., 85, 5793-5802, 1980.

Corliss, William R.

Scientific Satellites, 822 pp., NASA publication SP-133, U.S. Govt. Printing Office, 1967.

Cowling, Thomas Gilbert

On AlfvŽn's theory of magnetic storms and of the aurora, Terrestr. Magnetism and Atmosph. Electricity, 47, 209-214, 1942.

Cowling, Thomas Gilbert

Conductivity of an ionised gas, with applications, Proc. Roy. Soc. A., 183, 453-479, 1945.

Coroniti, Frederick V. and Charles F. Kennel

Changes in magnetospheric configuration during substorm growth phase, J. Geophys. Res., 77, 3361- 3370, 1972.

Cummings, W.D. and A.J. Dessler

Field-aligned currents in the magnetosphere, J. Geophys. Res., 72, 1007-1013, 1967.

Dalgarno, Alexander, W.B. Hanson, N.W. Spencer and E.R. Schmerling (c)

The Atmosphere Explorer mission, Radio Science, 8, 263-266, 1973.

Dassoulas, John (c)

The Triad spacecraft, APL Technical Digest (Applied Physics Laboratory of the Johns Hopkins Univ.), 12, 2-13, 1973.

Davis, Leo R. and J. M. Williamson

Low energy trapped protons, Space Research, 3, 365-375, North Holland Publ. Co., 1963.

Davis, Leo R. and J.M. Williamson

Outer zone protons, in Radiation Trapped in the Earth's Magnetic Field, Billy M. McCormac, editor, pp. 110-125, D. Reidel 1966.

Davis, T. Neil

The morphology of the auroral displays of 1957-1958, 2. Detail analyses of Alaska data and analyses of high-latitude data, J. Geophys. Res., 67, 75-110, 1962.

Davis, T. Neil

Magnetospheric convection pattern inferred from magnetic disturbance and auroral motion, J. Geophys. Res., 76, 5978-5984, 1971

DeForest, Sherman E. and Carl E. McIlwain

Plasma clouds in the magnetosphere, J. Geophys. Res., 76, 3587-3611, 1971.

Dessler, Alex J.

Discussion of paper by R.L. Arnoldy, R.A. Hoffman and J.R. Winckler, "Observation of the Van Allen radiation regions during August and September 1959," part 1, J. Geophys. Res., 65, 3487-3490, 1960.

Dessler, Alex J. (editor)

Physics of the Jovian Magnetosphere, xv + 544 pp., Cambridge Univ. Press, 1983.

Dessler, Alex J.

The Vernov radiation belt (almost), Science, 226, 915, 23 November 1984.

Dessler, Alex J. and Eugene N. Parker

Hydromagnetic theory of geomagnetic storms, J. Geophys. Res., 64, 2239-2252, 1959.

Dessler, AlexJ. and Ernest H. Vestine

Maximum total energy of the Can Allen Radiation Belt, J. Geophys. Res., 65, 1069-71, 1960.

Dessler, Alex J. and Jules A.Fejer

Interpretation of Kp index and M-region geomagnetic storms, Planet. Space Sci., 11, 505-511, 1963.

Dessler, Alex J. and R.D. Juday

Configuration of auroral radiation in space, Planet. Space Sci., 13, 63-72, 1965.

DeVorkin, David H.

Science with a Vengeance, xxii+404 pp., Springer-Verlag, 1992.

Dobrowolny, M. and V. Formisano

The structure of the Earth's bow shock, Rivista del Nuovo Cimento, 3, 419-489, 1973.

Drake, Frank D.

Discovery of the Jupiter Radiation Belts, in Serendipitous Discoveries in Radio Astronomy, K. Kellermann and B. Sheets, editors, p. 258-265, National Radio Astronomy Observatory, Green Bank, 1985.

Dungey, J.W.

Conditions for the occurence of electrical discharges in astrophysical systems, Philos. Mag., 44, 725-738 1953.

Dungey, James W.

Cosmical Electrodynamics, 183 pp., Cambridge Univ. Press, London 1958.

Dungey, James W.

Interplanetary magnetic field and the auroral zones, Phys. Rev. Letters, 6, 47-48, 1961.

Dungey, James W.

The structure of the exosphere, or, adventures in velocity in Geophysics, The Earth's Environment (Proceedings of the 1962 Les Houches Summer School), pp. 503-550, C. DeWitt, J. Hieblot and A. Lebeau, edditors, Gordon and Breach, NY 1963.

Dungey, James W.

The history of the magnetopause region, J.A.T.P., 40, 231-234, 1978.

Dungey, James W.

Memories, Maxims and Motives, J. Geophys. Res., 99, 19,189-197, 1994.

Dungey, James W.

Origins of the concept of reconnection and its application to the magnetopause: A historical view, in Physics of the Magnetopause, B.U.O.Sonnerup and P. Song, editors, p. 17-19, Amer. Geophys. Union, Washington, D.C. 1995a.

Eather, Robert H.

Majestic Lights, 323 pp., Amer. Geophys. Union, Washington, DC 1980.

Elphic, Richard C.

Fact, inference and speculation: what we know vs. what we believe about flux transfer events, in Physics of the Magnetopause, B.U.O.Sonnerup and P. Song, editors, Amer. Geophys. Union, Washington, D.C. (in press, 1994).

Erickson, Gary M.

On the cause of X-line formation in the near-earth plasma sheet: Results of adiabatic convection of plasma sheet plasma, p. 296-302 in Magnetic Reconnection in Space and Laboratory Plasmas, E.W. Hones, Jr., editor, AGU, Washington, DC, 1984.

Erickson, Gary M.

A quasi-static magnetospheric convection model in two dimensions, J. Geophys. Res., 97, 6505-6522, 1992.

Erickson, Gary M. and Richard A. Wolf

Is steady convection possible in the Earth's magnetotail? Geophys. Res. Let., 7, 897-900, 1980.

Evans, David S.

Precipitating electron fluxes formed by a magnetic field aligned potential difference, J. Geophys. Res., 79, 2853-58, 1974.

Evans, David S.

Evidence for low-altitude acceleration of auroral particles, p. 319-340 in Physics of Hot Plasma in the Magnetosphere, B. Hultqvist and L. Stenflo, eds., Plenum, NY, 1976a.

Evans, David S.

The acceleration of charged particles at low altitudes, p. 730-739 in Physics of Solar Planetary Environments, D.J. Williams, ed., Amer. Geophys. Union, Washington, DC 1976b.

Ezell, Linda Neuman

NASA Historical Data Book, Vol. II, Programs and Projects 1958-1968, 643 pp., NASA Publication SP-4012, 1988.

Fahleson, Ulf

Theory of electric field measurements conducted in the magnetosphere with electric probes, Space Sci. Rev., 7, 238-262, 1967.

Fairfield, Donald H. and Lawrence G. Cahill, Jr.

Transition region magnetic field and polar magnetic disturbances, J. Geophys. Res., 71, 155-169, 1966.

Fairfield, Donald H.

Polar magnetic disturbances and the interplanetary magnetic field, Space Research VIII, 107-119, 1967.

Fairfield, Donald H. and Norman F. Ness

Configuration of the geomagnetic tail during substorms, J. Geophys. Res., 75, 7032-7047, 1970.

Farley, T.A.

The growth of our knowledge of the Earth's outer radiation belt, Rev. Geophys., 1. 3-34, 1963.

Feldshtein, Yakov I.

Some problems concerning the morphology of auroras and magnetic disturbances at high latitude, Geomagnetism and Aeronomy, (English translation) 3, 183-192, 1963.

Felds(h)tein, Yakov I.

Polar auroras, polar substorms and their relationships with the dynamics of the magnetosphere, Rev. Geophys., 7, 179-218, 1969.

Ferraro, Vincent C.A.

Non-uniform rotation of the Sun and its magnetic field, Mon. Not. Roy.Astron.Soc., 97, 458-472, 1937.

Forbes, Terry G. and Eric R. Priest

A comparison of analytical and numerical models for steadily driven magnetic reconnection, Rev. Geophys., 25, 1583-1607, 1987.

Forbush, Scott E.

Three unusual cosmic-ray increases possibly due to charged particles from the sun, Phys. Rev., 70, 771-772, 1946.

Foster, John S, T. Kenneth Fowler and Frederick E. Mills

Nicholas C. Christofilos (obituary), Physics Today, 26, 109-115, January 1973.

Frank, Louis A.

Efficiency of a Geiger-Mueller tube for non-penetrating electrons, J. Franklin Inst., 273, 91-106, 1962.

Frank, Louis A.

On the extraterrestrial ring current during geomagnetic storms, J. Geophys. Res., 72, 3753-67, 1967 (ring current ions with OGO 3).

Frank, Louis A.

Relationship of the plasma sheet, ring current trapping boundary and plasmapause near the magnetic equator and local midnight, J. Geophys. Res., 76, 6971-6979, 1971.

Frank, Louis A., et al.

The theta aurora, J. Geophys. Res., 91, 3177-3224, 1986.

Frank, Louis A. and Kenneth L. Ackerson

Observations of charged particle precipitation into the auroral zone, J. Geophys. Res., 76, 3612-3643, 1971.

Frank, Louis A., K.L. Ackerson and R.P. Lepping

On hot tenuous plasmas, fireballs and boundary layers in the earth's magnetotail, J. Geophys. Res., 81, 5859-5881, 1976.

Frank, Louis A. and K.L. Ackerson

Reply, J. Geophys. Res., 82, 5641-5643, 1977.

Frank, Louis A., R.J. DeCoster and K.L. Ackerson

Reply, J. Geophys. Res., 83, 1187-1190, 1978a.

Frank, Louis A., R.J. DeCoster and K.L. Ackerson

Reply, J. Geophys. Res., 83, 3365-3366, 1978b.

Frank, Louis A. and Kenneth L. Ackerson

Several recent findings concerning the dynamics of the Earth's magnetotail, Space Science Reviews, 23, 375-392, 1979.

Frank, Louis A. and John D. Craven

Imaging results from Dynamics Explorer 1, Rev. Geophys., 26, 249-283, 1988.

Frank, Louis A. with Patrick Huyghe

The Big Splash, 255 pp., Birch Lane press, Carol Publ. Group, New York, 1990.

Franklin, Kenneth L.

An account of the discovery of Jupiter as a radio source, Astron J., 64, 37-39, 1959.

Franklin, Kenneth L.

The discovery of Jupiter Bursts, in Serendipitous Discoveries in Radio Astronomy, K. Kellermann and B. Sheets, editors, p. 252-257 National Radio Astronomy Observatory, Green Bank, 1985.

Freden, S.C. and R.S. White

Protons in the Earth's magnetic field, Phys. Rev. Letters, 3, 9-11, 1959.

Friedman, Herbert

From ionosonde to rocket sonde, J. Geophys. Res., 99, 19,143-153, 1994.

Friis-Christensen, Egil, K. Lassen, J.M. Wilcox, W. Gonzalez and D.S. Colburn

Interplanetary magnetic sector polarity from polar geomagnetic field observations, Nature (Physical Sciences), 233, PS48-PS50, 20 September 1971.

Fritz, Hermann

Das Polarlicht, Brockhaus, Leipzig, 1881.

Fujii, R., Takesi Iijima, Thomas A. Potemra and Masahisa Sugiura

Seasonal dependence of large-scale Birkeland currents, Geophys. Res. Lett., 8, 1103-1106, 1981.

Fukushima, Naoshi

Equivalence in ground geomagnetic effect of Chapman-Vestine's and Birkeland-Alfven's current systems for polar magnetic storms, Rep. Ionos.Space Res.Jap., 23, 219-227, 1969.

Fukushima, Naoshi

Generalized theorem for no ground magnetic effect of vertical currents connected with Pedersen currents in the uniform-conductivity ionosphere, Rep. Ionos.Space Res.Jap., 30, 35-40, 1976.

Fukushima, Naoshi

Some topics and historical episodes in geomagnetism and aeronomy, J. Geophys. Res., 99, 19,113-142, 1994.

Giovanelli, R.G.

Magnetic and electric phenomena in the sun's atmosphere associated with sunspots, Month. Not. Roy. Astr. Soc., 107, 338-355, 1947.

Goertz, Christoph K.

Double layers and electrostatic shocks in space, Rev. Geophys., 17, 418-426, 1979.

Goertz, Christoph K. and Robert A. Smith

The thermal catastrophe model of substorms, J. Geophys. Res., 94, 6581-96, 1989.

Gold, Thomas

Motions in the magnetosphere of the Earth, J. Geophys. Res., 64, 1219-1224, 1959.

Gombosi, Tamas I., Bengt Hultqvist and Yohsuke Kamide, editors (c)

Pioneers of Space Physics, J. Geophys. Res., 99, 19,099-212, 1994.

Gosling, John T.

The solar flare myth, J. Geophys. Res., 98, 18,937-18,949, 1993.

Grad, Harold

Variational principle for a guiding center plasma, Phys. Fluids, 9, 225-251, 1966.

Greenstadt, Eugene W. and Robert W. Fredricks

Shock systems in collisionless space plasmas, p. 3-43 in vol 3 of Solar System Plasma Physics, C.F. Kennel, L.J. Lanzerotti and E.N. Parker, editors, North Holland 1979.

Gurnett, Donald A.

The earth as a radio source: terrestrial kilometric radiation, J. Geophys. Res., 79, 4227-4238, 1974.

Gustafsson, Georg

On the orientation of auroral arcs, Planet. Space Sci., 15, 277-294, 1967.

Hallinan, Thomas J.

Auroral spirals, 2. Theory, J. Geophys. Res., 81, 3959-3965, 1976.

Hanson, William B. and R. A. Heelis

Techniques of measuring bulk gas motions from Satellites, Space Sci. Instr., 1, 493-524, 1975.

Hapgood, M.A.

Space physics coordinate transformations: a user's guide, Planet. Space Sci., 40, 711-717, 1992.

Harang, Leiv

The Aurorae, x + 166 pp., John Wiley & Sons, New York, 1951.

Hardy, David A.

H.Kent Hills and John W. Freeman, Jr., A new plasma regime in the distant geomagnetic tail,Geophys. Res. Lett. , 2, 169-172, 1975

Hardy, David A., H. Kent Hills and John W. Freeman, Jr.

Occurence of lobe plasma at lunar distance, J. Geophys. Res., 84, 72, 1979.

Hau, Lin-Ni, R.A. Wolf, C.H. Voigt and C.C. Wu

Steady state magnetic field configurations for the Earth's magnetotail, J. Geophys. Res., 94, 1303-16, 1989.

Heelis, Rodney A., W.B. Hanson and J.L. Burch

Ion convection velocity reversals in the dayside cleaft, J. Geophys. Res., 81, 3803-3809, 1976.

Heelis, Rodney A., W.B. Hanson, C.R. Lippincott, L.H. Harmon, B.J. Holt, J.E. Doherty and R.A. Power

The ion drift meter for Dynamics Explorer B, Space Sci. Instrum., 5, 511-521, 1981.

Helliwell, Robert A.

Whistlers and Related Ionospheric Phenomena, 349 pp., Stanford University Press, Stanford, CA 1965.

Heppner, James P.

The world magnetic survey, Space Sci. Rev., 2, 315-354, 1963.

Heppner, James D.

Recent measurements of the magnetic field in the outer magnetosphere and boundary regions, Space Sci. Rev., 7, 166-190, 1967.

Heppner, James P.

Electric field variations during substorms: Ogo-6 measurements, Planet. Space Sci., 20, 1475-1498, 1972a.

Heppner, James P.

The Harang discontinuity in auroral belt ionospheric currents, Geophys. Publ., 29, 105-120, 1972b.

Heppner, James P.

Polar cap electric field distributions related to the interplanetary magnetic field direction, J. Geophys. Res., 77, 4877-4887, 1972c.

Heppner, James P.

Empirical models of high-latitude electric fields, J. Geophys. Res., 82, 1115-1125, 1977.

Heppner, J.P., N.F. Ness, C.S. Scearce a,d T.L. Skillman

Explorer 10 magnetic field measurements, J. Geophys. Res., 68, 1-46. 1963.

Heppner, James P. and Nelson C. Maynard

Empirical high-latitude electric field models, J. Geophys. Res., 92, 4467-4489, 1987.

Hess, Wilmot N.

Energetic perticles in the inner Van Allen Belt, Space Sci. Rev., 1, 278-312, 1962.

Hess, Wilmot N., editor

The Physics of Solar Flares (proc. of AAS-NASA Symposium), NASA SP-50, 1964.

Hess, Wilmot N.

The Radiation Belt and Magnetosphere, viii+548 pp., Blaisdell Publ. Co., Waltham 1968.

Hess, Wilmot N., G. Mead and M.P. Nakada

Advances in particles and field research in the satellite era, Reviews of Geophysics, 3, 521-570, 1965.

Hesse, Michael and Karl Schindler

A theoretical foundation of general magnetic reconnection, J. Geophys. Res., 93, 5559-5567, 1988.

Hines, Colin

The magnetopause: a new frontier in space, Science, 141, 130-136, 1963.

Hines, Colin O.

Hydromagnetic motions in the magnetosphere, Space Sci. Rev., 3, 342-379, 1964

Hines, Colin O. and colleagues

The Upper Atmosphere in Motion, 1027 pp., Geophysical Monograph 18, Amer. Geophys. Union, Washington, D.C. 1974.

Hines, Colin O.

Origins of the 1961 Axford-Hines paper on magnetospheric convection, Eos, 67, 634, 1986. (Reprinted in History of Geophysics, 4, S. Gillmor, editor, pp. 97-98, Amer. Geophys. Union, Washington, D.C. 1990)

Hoffman, Robert A.

The magnetosphere, ionosphere and atmosphere as a system: Dynamics Explorer 5 years later, Rev. Geophys., 26, 209-214, 1988.

Hoffman, Robert A., G.D. Hogan and R.C. Maehl (c)

Dynamics Explorer spacecraft and ground operations systems, Space Sci. Instrument., 5, 349-367, 1981.

Holzer, Robert E. and J.A. Slavin

Magnetic flux transfer associated with expansions and contractions of the dayside magnetosphere, J. Geophys. Res., 83, 3831-3839, 1978.

Hones, Edward W., Jr.

The magnetotail: its generation and dissipation, in Physics of Solar-Planetary Environments, pp. 558-571, D.J. Williams, editor, Amer. Geophys. Union, Washington, D.C., 1976.

Hones, Edward J., Jr.

Substorm processes in the magnetotail: Comments on 'On hot tenuous plasmas, fireballs, and boundary layers in the Earth's magnetotail' by L.A. Frank, K.L. Ackerson and R.P. Lepping, J. Geophys. Res., 82, 5633-40 , 1977.

Hones, Edward W. Jr.

Comment on "on hot tenuous plasmas, fireballs and boundary layers in the Earth's magnetotail" by L.A. Frank. K.L. Ackerson and R.P. Lepping, J. Geophys. Res., 83, 1183-1186, 1978a.

Hones, E.W. Jr.

Processes at the magnetotail boundary: Comment on "on hot tenuous plasmas, fireballs and boundary layers in the Earth's magnetotail" by L.A. Frank. K.L. Ackerson and R.P. Lepping, J. Geophys. Res., 83, 2216-2227, 1978b.

Hones, E.W. Jr.

Some characteristics of rapidly flowing magnetotail plasmas: further comments on "on hot tenuous plasmas, fireballs and boundary layers in the Earth's magnetotail" by L.A. Frank. K.L. Ackerson and R.P. Lepping, J. Geophys. Res., 83, 3358-3364, 1978c.

Hones, Edward W., Jr.

Transient phenomena in the magnetotail and their relation to substorms, Space Sci. Rev., 23, 393-410, 1979.

Hones, Edward W., Jr. (ed.)

Magnetic Reconnection in Space and Laboratory Plasmas, Geophysical Monograph 30, AGU, Washington, DC, 1984a.

Hones, Edward W., Jr.

Historical note on Ronald G. Giovanelli, pp. v-vi in, Magnetic Reconnection in Space and Laboratory Plasmas, AGU, Washington, DC, 1984b.

Hones, Edward W., Jr.

J.R. Asbridge, S.J. Bame and I.B. Strong, Outward flow of plasma in the magnetotail following geomagnetic bays, J. Geophys. Res., 72, 5879-92, 1967.

Hones, Edward W., Jr.

S.I. Akasofu, P. Perreault, S.J. Bame and Sidney Singer, Poleward expansion of the auroral oval and associated phenomena in the magnetotail during auroral substorms, J. Geophys. Res., 75, 7060-7074, 1970.

Huang, Cheryl Y. and Louis A. Frank

A statistical study of the central plasma sheet: Implications for substorm models, Geophys. Res. Let., 13, 652-655, 1986.

Hughes, W.Jeffrey

Hydromagnetic Waves in the Magnetosphere, Rev. Geophys., 21, 508-520, 1983.

Hultqvist, Bengt (c)

The Viking project. Geophys. Res. Lett, 14, 379-382, 1987.

Hunten, Donald, M. and Thomas M. Donahue

Hydrogen glows from the terrestrial planets, Annu. Rev. Earth. Planet. Sci., 4, p. 265-292, 1976.

Iijima, Takesi and Thomas A. Potemra

The amplitude distribution of field-aligned currents at northern high latitudes observed by Triad, J. Geophys. Res., 81, 2165-2174, 1976a.

Iijima, Takesi and Thomas A. Potemra

Field-aligned currents in the dayside cusp observed by Triad, J. Geophys. Res., 81, 5971-5979, 1976b.

Ismail, Syed, D.D. Wallis and L.L. Cogger

Characteristics of polar cap sun-aligned arcs, J. Geophys. Res., 82, 4741-4749, 1977.

Iyemori, T., H. Maeda,and T. Kamei

Impulse response of geomagnetic indices to interplanetary magnetic field, J. Geomag. Geoelectr.,31, 1-9, 1979.

Jaggi, Radhe K. and Richard A. Wolf

Self-consistent calculation of the motion of a sheet of ions in the magnetosphere, J. Geophys. Res., 78, 2852-2866, 1973.

Jackson, John E. and James I. Vette

OGO Program Summary, 310 pp.NASA document SP-7601, NASA, Washington, D.C. 1975.

Johnson, Francis S.

The gross character of the geomagnetic field in the solar wind, J. Geophys. Res., 65, 3049-3051, 1960.

Johnson, Francis S.

The driving force for magnetospheric convection, Rev. Geophys., 16, 161-167, 1978.

Johnson, Richard G

Energetic ion composition in the Earth's magnetosphere, Rev. Geophys., 17, 696-704, 1979.

Kan. Joseph R.

Developing a global model of magnetospheric substorms, Eos, 71, 1083, 1086-7, 18 September 1990.

Kan, Joseph R., L. Zhu and S.-I. Akasofu

A theory of substorms: onset and subsidence, J. Geophys. Res., 93, 5624-5640,1988.

Keath, Edwin P, E.C. Roelof, C.O. Bostrom and D.J. Williams, Roelof

Fluxes of >50 keV protons and >30 keV electrons at about 35 RE 2. Morphology and flow patterns in the magnetotail, J. Geophys. Res., 81, 2315-26, 1976.

Kelley, Michael, C.

The Earth's Ionosphere--Plasma Physics and Electrodynamics, ix + 487 pp., Academic Press, 1989.

Kellogg, Paul J.

Possible explanation of the radiation observed by Van Allen at high altitudes in satellites, Nuovo Cimento, 11, 48-66, 1959.

Kellogg, Paul J.

Flow of plasma around the Earth, J. Geophys. Res., 67, 3805-3811, 1962.

Kennel, Charles F.

Consequences of a Magnetospheric Plasma, Rev. Geophys., 7, 379-419, 1969.

Kennel, Charles F.

Neil Mather Brice, 1934-1974, Eos, 66, 1353-1355, 1985. (Reprinted in History of Geophysics, 4, S. Gillmor, editor, pp. 253-255, Amer. Geophys. Union, Washington, D.C. 1990.)

Kennel, Charles F.

Critical Mach numbers in classical magnetohydrodynamics, J. Geophys. Res., 92, 13,427-13,437, 1987.

Kennel. Charles F., J.P. Edmiston and T. Hada

A quarter century of collisionless shock research, in Collisionless shocks in the heliosphere: a tutorial review, R. G. Stone and B.T. Tsurutani, editors, pp. 1-36, Geophysical Monograph 34, Amer. Geophys. Union, Washington, D.C. 1985.

Kennel, Charles F. and Harry E. Petschek

Limit on stably trapped particle fluxed, J. Geophys. Res., 71, 1-28, 1966.

Knight, S.

Parallel electric fields, Planet, Space Sci., 21, 741-750, 1973.

Langel, Robert A.

Near-Earth magnetic disturbance in total field at high latitude, 1. Summary of data from Ogo 2, 4 and 6, J. Geophys. Res., 79, 2663--2671, 1974

Lanzerotti, Louis J. and David J. Southwood

Hydromagnetic waves, p. 109-135 in vol. 3 of Solar System Plasma Physics, C.F. Kennel, L.J. Lanzerotti and E.N. Parker, eds., North Holland 1979.

Lee, Lou C. and Z.F. Fu

A Theory of magnetic flux transfer at the Earth's magnetopause, Geophys. Res. Lett.,12, 105-108, 1985.

Le Galley, Donald P.

Space Science, xviii+668 pp., John Wiley and Sons, 1963.

Lemaire, Joseph

The mechanisms of formation of the plasmapause, Ann. Geophys., 31, 175-190, 1975.

Lepping, Ronald P.

Characteristics of the magnetopauses of the magnetized planets, in Physics of the Magnetopause, B.U.O.Sonnerup and P. Song, editors, p. 61-70, Amer. Geophys. Union, Washington, D.C. 1995.

Levy, R.H., H.E. Petschek and G.L. Siscoe

Aerodynamic aspects of the magnetospheric flow, AIAA J., 2, 2065-2076, 1964.

Liemohn, Harold B.

The lifetimes of radiation belt protons with energies between 1 keV and 1 Mev, J. Geophys. Res., 66, 3593-3595, 1961.

Longanecker, Gerald W., and R.A. Hoffman (c)

S3-A spacecraft and experiment description, J. Geophys. Res., 78, 4711-4717, 1973.

Lopez, Ramon E. and Daniel N.Baker

Evidence for particle acceleration during magnetospheric substorms, Astroph.J. Suppl., 90, 531-539, 1994.

Ludwig, George H.

The orbiting geophysical observatories, Space Sci. Rev., 2, 175-218, 1963.

Lui, Anthony T.Y.

Extended consideration of a synthesis model for magnetospheric substorms, in Magnetospheric Substorms, J.R. Kan, T.A. Potemra, S. Kokubun and T. Iijima, editors, p. 43-60, Geophysical Monograph 64, Amer. Geophys. Union, Washington, D.C. 1991

Lui, Anthony T.Y. and C.D. Anger

A uniform belt of diffuse auroral emission seen by the Isis-2 scanning photometers, Planet. Space Sci., 21, 799-809, 1973.

Lui, Anthony T.Y.

R.W. McEntire and S.M. Krimigis, Evolution of the ring current during two geomagnetic storms, J. Geophys. Res., 92, 7459-7470, 1987.

Lui, Anthony T.Y. and D.C. Hamilton

Radial profiles of quiet-time magnetospheric parameters, J. Geophys. Res., 97, 19,325--19,332, 1992.

Manka, Robert H., T.A. Fritz, R.G. Johnson, R.A. Wolf, M.J. Teague and J.I. Vette

Overview of the IMS July 29, 1977, Magnetic Storm Analysis, J. Geophys. Res., 87, 5871-5880, 1982.

Mansurov, S.M.

New evidence of a relationship between magnetic fields in space and on Earth, Geomag. Aeron., 9, 622-623, 1969.

Mauk, Barry H. and C.-I. Meng

Plasma injection during substorms, Physica Scripta, T18, 128-139, 1987.

Mayaud, P.N.

Derivation, Meaning and Use of Geomagnetic Indices, vi+154 pp., Geophysical Monograph 22, Amer. Geophys. Union, 1980.

McIlwain, Carl E.

Direct measurement of particles producing visible auroras, J. Geophys. Res., 65, 2727-2747, 1960.

McIlwain, Carl E.

The radiation belts, natural and artificial, Science, 142, 355-361, 1963.

McPherron, Robert L.

Growth phase of magnetospheric substorms, J. Geophys. Res., 75, 5592-5599, 1970.

McPherron, Robert L.

Substorm related changes in the geomagnetic tail: the growth phase, Planet. Space Sci., 20, 1521-39, 1972.

McPherron, Robert L.

Magnetospheric Substorms, Rev. Geophys., 17, 657-681, 1979.

McPherron, Robert L., C. T. Russell and M. P. Aubry

Satellite studies of magnetospheric substorms on August 15, 1968, 9., Phenomenological model for substorms, J. Geophys. Res., 78, 3131-3149, 1973.

McPherron, Robert L. and J.N. Barfield

A seasonal change in the effect of field-aligned currents at synchronous orbit, J. Geophys. Res., 85, 6743-6746, 1980.

Mencke-Hansen, A., A. Bahnsen and N. D'Angelo

The cusp-magnetosheath interface, J. Geophys. Res., 81, 556-561, 1976.

Meng, C.-I., R.H. Holzworth and S.-I. Akasofu

Auroral circle--delineating the poleward boundary of the quiet auroral belt, J. Geophys. Res., 82, 164-172, 1977.

Meredith, Leslie H., M.B. Gottlieb and J.A. Van Allen

Direct detection of soft radiation above 50 kilometers in the auroral zone, Phys. Rev., 97, 201-205, 1955.

Mizera, Paul F. et al.

The aurora inferred from S3-3 particles and fields, J. Geophys. Res., 86, 2329-2339, 1981.

Mozer, Forrest et al.

Observation of paired electrostatic shocks in the polar magnetosphere, Phys. Rev. Lett., 38, 292-295, 1977.

Nagai, Tsugunobu, D.N. Baker and P.R. Higbie

Development of substorm activity in multiple-onset substorms at synchronous orbit, J. Geophys. Res., 88, 6994-7004, 1983.

Naugle, John E. (introducer)

Scientific Findings from Explorer VI, 381 pp., NASA document SP-54, U.S. Printing Office, 1965.

Ness, Norman F.

The Earth's magnetic tail, J. Geophys. Res., 70, 2989-3005, 1965.

Ness, Norman F.

The geomagnetic tail, Rev. Geophys., 7, 97-127, 1969.

Ness, Norman F.

Magnetometers for space research, Space Sci. Rev., 11, 459-554, 1970.

Ness, Norman F.

The magnetic fields of Mercury, Mars and Moon, Ann. Rev. Earth Planet. Sci., 7, 249-288, 1979.

Ness, Norman F.

Magnetotail research: the early years, pp. 11-20 in Magnetotail Physics, edited by A.T.Y. Lui, The Johns Hopkins University Press, 1987.

Ness, Norman F., C.S.Scearce and J.B. Seek

Initial results of the IMP-1 magnetic field experiment, J. Geophys. Res., 69, 3531-3569, 1964.

Ness, Norman F., M.H. Acuna, R.P. Lepping, L.F.Burlaga, K.W.Behannon and F.M.Neubauer

Magnetic field studies at Jupiter by Voyager 2: Preliminary results, Science, 206, 966-972, 1979.

Newcomb, William A.

Motion of magnetic lines of force, Ann. Phys., NY, 3, 347-385, 1958.

Newell, Homer E., Jr., (editor)

Sounding Rockets, 334 pp., McGraw Hill, NY 1959.

Newell, Homer E., Jr.

Beyond the Atmosphere, NASA Special Publication 4211, xviii + 497 pp., , Govt. Printing Office, Washington, DC 1980.

Nishida, Atsuhiro

Formation of plasmapause, or magnetospheric plasma knee, by the combined action of magnetospheric convection and plasma escape from the tail, J. Geophys. Res., 71, 5669-5679, 1966.

Nishida, Atsuhiro, and T. Mukai, T. Yamamoto, Y. Saito, S. Kokubun and K. Maezawa

Geotail observations of magnetospheric convection in the distant tail at 200 RE in quiet times, J. Geophys. Res., 100, 22,663-22,675 , 1995.

Northrop, T.G. and E. Teller

Stability of the adiabatic motion of charged particles in the earth's field, Phys. Rev., 117, 215-225, 1960.

O'Brien, Brian J.

Lifetime of outer zone electrons and their precipitation into the atmosphere, J. Geophys. Res., 67, 3687-3706, 1962.

O'Brien, Brian J.

Review of studies of trapped radiation with satellite-borne apparatus, Space Science Reviews, 1, 415-484, 1963.

O'Brien, Brian J.

Energetic charged particles in the magnetosphere, p. 169-211 in Solar-Terrestrial Physics, J.W. King and W.S. Newman, eds., Academic Press, London 1967.

O'Brien, Brian J., C.D. Laughlin and D.A. Gurnett (c)

High-latitude geophysical studies with satellite Injun 3, 1. Description of the satellite, J. Geophys. Res., 69, 1-12, 1964.

O'Brien, Brian J. and H. Taylor

High-latitude geophysical studies with the satellite Injun III, 4. Auroras and their excitation, J. Geophys. Res., 69, 45-63, 1964.

Odishaw, Hugh and Stanley Ruttenberg (eds.)

Geophysics and the IGY, v+210 pp., Geophysical Monograph 2, American Geophysical Union, 1958.

Ogilvie, Keith W., A. Durney and T. von Rosenvinge (c)

Description of experimental investigations and instruments for the ISEE spacecraft, IEEE Trans. Geoscience Electr., GE-16, 151-153, 1978.

Parker, Eugene N.

The solar-flare phenomenon and the theory of reconnection and annihilation of magnetic fields, Astrophys. J. Suppl., 8, Supplement #77, 177-211, 1963.

Papadopoulos, Konstantinos

A review of anomalous resistivity for the ionosphere, Rev. Geophys., 15, 113-127, 1977.

Paschmann, Goetz, G. Haerendel, N. Sckopke and H. Rosenbauer

Plasma and magnetic field characteristics of the distant polar cusp near local noon: the entry layer, J. Geophys. Res., 81, 2883-2899, 1976.

Paschmann, Goetz, B.U.O. Sonnerup, I. Papamastorakis, N. Sckopke, G. Haerendel, S.J.

Bame, J.R. Asbridge, J.T. Gosling, C.T. Russell and R.C. Elphic Plasma acceleration at the Earth's magnetopause: evidence for reconnection, Nature, 282, 283-286, 1979.

Perreault, Paul and Syun-Ichi Akasofu

A study of geomagnetic storms, Geophys. J. Roy. Astr. Soc., 54, 547-573, 1978.

Persson, Hans

Electric field along a magnetic line of force in a low-density plasma, Phys. Fluids, 6, 1756-1759, 1963.

Persson, Hans

Electric field parallel to the magnetic field in a low density plasma, Phys. Fluids, 9, 1090-1098, 1966.

Petschek, Harry E.

Magnetic field annihilation, p. 425-439 in The Physics of Solar Flares (proc. of AAS-NASA Symposium), Wilmot N. Hess, ed., NASA SP-50, 1964.

Petschek, Harry E.

Concept of fast reconnection, in Physics of the Magnetopause, B.U.O.Sonnerup and P. Song, editors, p. 21-28Amer. Geophys. Union, Washington, D.C., 1995.

Pickering, William H.

History of the Juno cluster system, in Astronautical Engineering and Science, pp. 201-214., Ernest Stuhlinger, Frederick I. Ordway III, Jerry C. McCall and George C. Bucher, editors, McGraw Hill, 1963.

Pike, Charles P. and J.A. Whalen

Satellite observations of auroral substorms, J. Geophys. Res., 79, 985-1000, 1974.

Pomerantz, Martin A.

Scott E. Forbush 1904-1984, Eos, 65, 473-474, 1984 (reprinted in p. 187-189 of History of Geophysics, vol 2, C.S. Gillmor, ed., Amer. Geophys. Union, Washington, DC 1986).

Rees, Manfred H. and R.G. Roble

Observations and theory of the formation of stable auroral arcs, Rev. Geophys., 13, 201-242, 1975.

Reiff, Patricia H., Robert W. Spiro and Thomas W. Hill

Dependence of polar cap potential drop on interplanetary parameters, J. Geophys. Res., 86, 7639-7648, 1981 (erratum, 87, 2579).

Reiff, Patricia and J.L. Burch

IMF By-dependent plasma flow and Birkeland currents in the dayside magnetosphere, 2. A global model for northward and southward IMF, J. Geophys. Res., 90, 1595-1609, 1985.

Rich, Frederick J. and M. Susan Gussenhoven

The absence of region 1/region 2 field-aligned currents during prolonged quiet times, Geophys. Res. Lett., 14, 689-692, 1987.

Roelof, Edward C., E.P. Keath and T. Iijima

Fluxes of >50 keV protons and >30 keV electrons at about 35 RE 1. Velocity anisotropies and plasma flow in the magnetotail, J. Geophys. Res., 81, 2304-14, 1976.

Roelof, Edward C. and David G. Sibeck

Magnetopause shape as bivariate function of interplanetary magnetic field Bz and solar wind dynamic pressure, J. Geophys. Res., 98, 21,421-450, 1993; correction, J. Geophys. Res., 99, 8787-88, 1994.. [2.6]

Rosenbauer, Helmut, H. GrŸnwaldt, M.D. Montgomery, G. Paschmann and N. Sckopke

Heos 2 plasma observations in the distant polar magnetosphere: the plasma mantle, J. Geophys. Res., 80, 2723-2737, 1975.

Rosenbluth, Marshall N. and Conrad L. Longmire

Stability of plasma confined by magnetic fields, Ann. Phys., 1, 120-140, 1957.

Rostoker, Gordon

Polar magnetic substorms, Rev. Geophys., 10,157-211, 1972.

Rostoker, Gordon

Geomagnetic indices, Rev. Geophysics, 10, 935-950, 1972.

Rostoker, Gordon, S.-I. Akasofu, J. Foster, R.A. Greenwald, Y. Kamide, K. Kawasaki, A.T.Y. Lui, R.L. McPherron and C.T. Russell

Magnetospheric Substorms--definitions and signatures, J. Geophys. Res., 85, 1663-1668, 1980.

Rostoker, Gordon and Timothy Eastman

A boundary layer model for magnetospheric substorms, J. Geophys. Res., 92, 12,187-12,201, 1987.

Rufenach, Clifford L., R.L. McPherron and J. Schaper

The quiet geomagnetic field at geosynchronous orbit and its dependence on solar wind dynamic pressure, J. Geophys. Res., 97, 25-42, 1992.

Russell, Christopher T.

Geophysical coordinate transformations, Cosmic Electrodyn., 2, 184-196, 1971.

Russell, Christopher T. and Richard C. Elphic

Initial ISEE magnetometer results: magnetopause observations, Space Sci. Rev., 22, 681-715, 1978.

Russell, Christopher T. and Richard C. Elphic

ISEE observations of flux transfer events at the dayside magnetopause, Geophys. Res. Let., 6, 33-36, 1979.

Schield, Milo A., J. W. Freeman and A. J. Dessler

A source for field-aligned currents at auroral latitudes, J. Geophys. Res., 74, 247-256, 1969.

Schindler, Karl and J. Birn

Magnetospheric physics, Physics Reports, 47, 109-165, 1978.

Science (Pioneer 10 at Jupiter) 183, 301-324, 1974.

Science (Mariner 10 at Mercury), 185, 141-184, 1975a.

Science (Pioneer 11 at Jupiter), 188, 445-477, 1975.

Science (Voyager 1 at Jupiter), 204, 945-1008, 1979a.

Science (Voyager 2 at Jupiter), 206, 925-996, 1979b.

Science (Pioneer 11 at Saturn), 207, 400-453, 1980.

Science (Voyager 1 at Saturn), 212, 159-243, 1981.

Science (Voyager 2 at Saturn), 215, 499-594, 1982.

Science (Voyager 2 at Uranus), 233, 39-109, 1986.

Science (Voyager 2 at Neptune), 246, 1417-1501, 1989.

Science (Ulysses at Jupiter), 256, 1487-1502, 1992.

Sckopke, Norbert

A general relation between the energy of trapped particles and the disturbance field near Earth, J. Geophys. Res., 71, 3125-3130, 1966.

Sharp, Richard D., Richard G. Johnson, Edward G. Shelley and K.K. Harris

Energetic O+ ions in the magnetosphere, J. Geophys. Res., 79, 1844-1850, 1974.

Sharp, Richard D., R.G. Johnson and E.G. Shelley

Observations of an ionosphric acceleration mechanism producing energetic (keV) ions primarily normal to the geomagnetic field directions, J. Geophys. Res., 82, 3324-3328, 1977.

Shawhan, Stanley D.

Magnetospheric plasma waves, p. 211-270 in vol. 3 of Solar System Plasma Physics, C.F. Kennel, L.J. Lanzerotti and E.N. Parker, eds., North Holland 1979.

Shelley, Edward G., R.G. Johnson and R.D. Sharp

Satellite observations of energetic heavy ions during a geomagnetic storm, J. Geophys. Res., 77, 6104-6110, 1972.

Shelley, Edward G., R.D. Sharp and R.G. Johnson

Satellite observations of an ionospheric acceleration mechanism, Geophys. Res. Lett., 3, 654-656, 1976.

Shepherd, Gordon G.

Dayside cleft aurora and its ionospheric effects, Rev. Geophys., 17, 2017-2033, 1979.

Sibeck, David G., R.E. Lopez and E.C. Roelof

Solar wind control of the magnetopause shape, location and motion, J. Geophys. Res., 96, 5489-5495, 1991.

Silsbee, H.C. and E.H. Vestine

Geomagnetic bays, their frequency and current systems, J. Geophys. Res., 47, 195-208, 1942.

Simpson, J.A.

A physicist in the world of geophysics and space, J. Geophys. Res., 99, 19,159-73, 1995.

Singer, S. Fred

A new model of magnetic storms and aurorae, Eos (Transact. Amer. Geophys. Union), 38, 175-190, 1957

Singer, S. Fred

"Radiation belt" and trapped cosmic ray albedo, Phys.Rev. Letters, 1, 171-173, 1958.

Singer, S.Fred and Allen M. Lencheck

Geomagnetically trapped radiation, Progress in Elementary Particle and Cosmic Ray Physics, VI, p. 247-335, North Holland Publ., Amsterdam 1962.

Siscoe, George L.

What's in the name "Magnetospheric substorm"?, J. Geophys. Res., 85, 1643-4, 1980.

Slavin, James A., Edward J. Smith, David G. Sibeck, Daniel N. Baker, Ronald D. Zwickl and Syun-Ichi Akasofu

An ISEE 3 study of the average and substorm conditions in the distant magnetotail, J. Geophys. Res., 90, 10,875-10,895, 1985.

Smith, Edward J.

Theoretical and experimental aspects of ring currents, in Space Science, edited by Donald LeGalley, pp. 316-373, John Wiley, New York, 1963.

Smith, Paul H., Robert A. Hoffman and Theodore A. Fritz

Ring current proton decay by charge exchange, J. Geophys. Res., 81, 2701-2708, 1976.

Sonnerup, Bengt U.O.

Magnetic field reconnection, p. 45-108 in vol. 3 of Solar System Plasma Physics, C.F. Kennel, L.J. Lanzerotti and E.N. Parker, eds., North Holland 1979.

Sonnerup, Bengt U.O. et al.

Evidence for magnetic field reconnection at the Earth's magnetopause, J. Geophys. Res., 86, 10,049-10,067, 1981.

Spiro, Robert W. and Richard A. Wolf

Electrodynamics of convection in the inner magnetosphere, in Magnetospheric Currents, T.A. Potemra, editor, p. 247-259, Geophysical Monograph 28, Amer. Geophys. Union, Washington, D.C., 1984.

Spitzer, Lyman Jr.

Physics of Fully Ionized Gases, Interscience, NY, 1956 (2nd ed. 1962).

Stern, David P.

The motion of magnetic field lines, Space Sci. Rev., 6, 147-173, 1966.

Stern, David P.

Large-scale electric fields in the Earth's magnetosphere, Rev. Geophys., 15, 156-194, 1977.

Stern, David P.

Energetics of the magnetosphere, Space Sci. Rev., 39, 193-213, 1984.

Stern, David P.

A conversation with Jim Dungey, Eos, 67, 1394-5, 1986.

Stern, David P.

A brief history of magnetospheric physics before the spaceflight era, Rev. Geophys., 27, 103-114, 1989.

Stern, David P.

The Substorm, Eos, 70, 130, 28 February 1989.

Stern, David P.

Substorm Electrodynamics, J. Geophys. Res., 95, 12,057-12067, 1990.

Stern, David P.

The beginning of substorm research, p. 11-14 in Magnetospheric Substorms, J.R.Kan, T.A.Potemra, S. Kokubun and T. Iijima, eds., Geophysical Monograph 64, Amer. Geophys. Union, Washington, DC 1991.

Stern, David P.

The linkage between the ionosphere and the plasma sheet, J. Geomag. Geoelectr., 44, 1109-1120, 1992.

Stern, David P. and Mauricio Peredo

The exploration of the magnetosphere, internet document http://www~spof.gsfc.nasa.gov/Education/Intro.html (world-wide web), 1995.

Stone, Robert G.

Research results from the Radio Astronomy Explorer, Proceedings of the AIAA 6th Annual Meeting (Anaheim, California 20-24 October, 1969; AIAA Paper 69-1049, 1969.

Sugiura, Masahisa

Identification of the polar cap boundary and the auroral belt in the high-latitude magnetosphere: A model for field-aligned currents, J. Geophys. Res., 80, 2057-2068, 1975.

Sugiura, Masahisa and T.N. Davis

Auroral electrojet activity index AE and its universal time variations, J. Geophys. Res., 71, 785-801, 1966.

Svalgaard, Leif

Sector structure of the interplanetary magnetic field and daily variation of the geomagnetic field at high latitudes, Geophys. Paper R-6, Danish Meteorolog. Inst., Copenhagen, 1968.

Svalgaard, Leif

Interplanetary magnetic-sector structure, 1926-1971, J. Geophys. Res., 77, 4027-4034, 1972.

Svalgaard, Leif

Polar cap magnetic variations and their relationship with the interplanetary magnetic sector structure, J. Geophys. Res., 78, 2064-2078, 1973.

Sweet, Peter A.

The effect of turbulence on a magnetic field, Mon. Not. Roy. Astr. Soc., 110, 69-83 , 1950.

Sweet, Peter A.

The neutral point theory of solar flares, p. 123-134 in Electromagnetic Phenomena in Cosmical Physics, B. Lehnert, ed., Cambridge U. Press, London 1958.

Tsuruda, Koichiro, and Hiroshi Oya (c)

Introduction to the Exos-D (Akebono) project, Geophys. Res. Lett., 18, 293-5, 1991.

Tsyganenko, Nikolai A., D.P. Stern and Z. Kaymaz

Birkeland currents in the plasma sheet, J. Geophys. Res., 98, 19,455-19,464, 1993.

Van Allen, James A.

Observation of high intensity radiation by satellites 1958 alpha and 1958 gamma, IOWA Univ. preprint SUI 60-13, reprinted in p. 58-75, Space Science Comes of Age, P.A. Hanle and V.D. Chamberlain, editors, Smithsonian Inst. Press, Washington, DC 1981.

Van Allen, James A.

Origins of Magnetospheric Physics, 144 pp., Smithsonian Inst. Press, Washington, DC 1983a.

Van Allen, James A.

Genesis of the International Geophysical Year, Eos, 64, 977, 1983b (reprinted on p. 49 in History of Geophysics, vol.1, C.S. Gillmor, ed., Amer. Geophys. Union, 1984).

Van Allen, James, A.

What is a space Scientist? An autobiographical example, Ann. Rev. Earth. Planet. Sci., 18, 1-26, 1990.

Van Allen, James A. (ed.)

Cosmic Rays, The Sun and Geomagnetism: The Works of Scott E. Forbush, 472 pp., AGU, Washington, DC, 1993.

Van Allen, James A.

Early rocket observations of auroral bremstrahlung and its absorption in the mesosphere, J. Geophys. Res., 100, 14,485-497, 1995.

Van Allen, James A., George H. Ludwig, Ernest C. Ray and Carl E. McIlwain

Observation of high intensity radiation by satellites 1958 Alpha and Gamma, Jet Propulsion, 28, 588-592, 1958.

Van Allen, James A., C.E. McIlwain and G.H. Ludwig

Radiation observations with satellite 1958 epsilon, J. Geophys. Res., 64, 271-286, 1959.

Van Allen, James A. and L. A. Frank

Radiation measurement to 658,300 km with Pioneer IV, Nature, 184, 219-224, 1959.

Vasyliunas, V.M.

A survey of low-energy electrons in the evening sector of the magnetosphere with OGO 1 and OGO 3, J. Geophys. Res., 73, 2839--2884, 1968.

Vasyliunas, Vytenis M.

Mathematical models of magnetospheric convection and its coupling to the ionosphere, p. 60-71 in Particles and Fields in the Magnetosphere, B.M. McCormac, ed., D. Reidel 1970.

Vasyliunas, Vytenis M.

The interrelationship of magnetospheric processes, p. 29-38 in Earth's Magnetospheric Processes, B.M. McCormac, ed., D. Reidel, 1972.

Vasyliunas, Vytenis M.

Theoretical Models of Magnetic Field Merging, 1, Rev. Geophys., 13, 303-336, 1975.

Vasyliunas, Vytenis M. and Richard A. Wolf

Magnetospheric substorms: Some problems and controversies, Rev. Geophys., 11, 181-189, 1973.

Vernov, S.N., N.L. Grigorov, I.P. Ivanenko, A.I. Lebedinskii, V.S. Murzin and A.E. Chudakov

Possible mechanism of production of "terrestrial corpuscular radiation" under the action of cosmic rays, Soviet Physics (Doklady), 4, 154-157, 1959 (in Russian Doklady 125, 304-307, 1959).

Vestine, Ernest H. and S. Chapman

The electric current system of geomagnetic disturbance, J. Geophys. Res., 43, 351-382, 1938.

Viking Science Team

The Viking program, Eos, 67, 793-795, 21 October 1986.

Voigt, G.-Hannes, and R.-A. Wolf

Quasi-static magnetospheric MHD processes and the "Ground State" of the magnetosphere, Rev. Geophys., 26, 823-843, 1988.

Von Braun, Wernher

The Redstone, Jupiter and Juno, in The History of Rocket Technology, pp. 107-121, E.M.Emme, editor, Wayne State University, Detroit 1964.

Walen, C.

On the distribution of the solar general magnetic field and remarks concerning the geomagnetism and the solar rotation, Arkiv fšr Matematik Astronomi och Fysik, 33-A, no. 18, 1946.

Walker, Raymond J., T. Ogino, J. Raeder and M. Ashour-Abdalla

A global magnetohydrodynamic simulation of the magnetosphere when the interplanetary magnetic field is southward: the onset of magnetotail reconnection, J. Geophys. Res., 98, 17,235-17,249, 1993.

White, R. Stephen

The Earth's radiation belts, Physics Today, 19, 25-38, October 1966.

White, R. Stephen

High energy proton radiation belt, Rev. Geophys., 11, 595-632, 1973.

Wilcox, John M. and N.F. Ness

A quasi-stationary co-rotating structure in the interplanetary medium, J. Geophys. Res., 70, 5793-5806, 1965.

Wilcox, John M.

The interplanetary magnetic field, Space Sci. Rev., 8, 258-328, 1968.

Wilcox, John M.

Inferring the interplanetary magnetic field by observing the polar geomagnetic field, Rev. Geophys., 10, 1003-1014, 1972.

Williams, Donald J.

Ring Current and Radiation Belts, Rev. Geophys. , 25, 570-578, 1987.

Williams, Donald J., E.C. Roelof and D.G. Mitchell

Global magnetospheric imaging, Rev. Geophys., 30, 183-208, 1992.

Winckler, John R. and Laurence E. Peterson

Large auroral effect on cosmic ray detectors observed at 8 g/cm2 atmospheric depth, Phys. Rev., 108, 903-4, 1957.

Winckler, John R., Laurence E. Peterson, Roger Arnoldy and Robert Hoffman

X rays from visible aurorae at Minneapolis, Phys. Rev., 110, 1221-1231, 1958.

Wygant, John R., Roy B. Torbert and Forrest S. Mozer

Comparison of S3-3 polar cap potential drops with the interplanetary magnetic field and models of magnetopause reconnection, J. Geophys. Res., 88, 5727-35, 1983.

Yaeger, D.M. and L.A. Frank

Low energy electron intensities at large distances over the Earth's polar cap, J. Geophys. Res., 81, 3966-3976, 1976.

Zmuda, Alfred J., J.H. Martin and F.T. Heuring

Transverse magnetic disturbances at 1100 km in the auroral region, J. Geophys. Res., 71, 5033-5045, 1966.

Zmuda, Alfred J. and James C. Armstrong

The diurnal flow pattern of field-aligned currents, J. Geophys. Res., 79, 4611-4619, 1974.

Captions of Figures

1. Explorer 1

2. Counting rate of Explorer 3 during a pass through the radiation belt. The highest rate was encountered during the segment of zero counts.

3. Counting rates of Pioneers 3 and 4, during traversals of the outer radiation belt [Van Allen and Frank, 1959].

4. Regions and currents of the Earth's magnetosphere, representing the state of our knowledge around 1970 [Lopez and Baker, 1994]. A small normal field component on the magnetopause allows some interplanetary field lines to link up with the Earth's field.

5a. Schematic view of the convection pattern produced in a closed magnetosphere by viscous-like forces, as envisioned by Axford and Hines.

5b. Schematic view of the convection in Figure 5a when mapped along field lines to the polar cap. Ideally, the contours are also equipotentials of the electric field, which near the center of the pattern is directed from dawn to dusk.

6. Magnetic merging at an X-type neutral line. Solid lines are magnetic field lines, dashed lines flow lines of the plasma (after Sonnerup [1979]).

7. Schematic view of Dungey's original view of the open magnetosphere, for a purely southward interplanetary magnetic field (IMF).

8. Transmission of electric fields along open field lines and to the cross-tail circuit.
9. Cartoon of the connection of the IMF to the magnetosphere, for various IMF orientations: (a) purely southward IMF; (b) southward slanting IMF (c) northward slanting IMF.

10. An example of the auroral energy spectrum, from Franck and Ackerson, [1971].

11. The proposed circuit of Birkeland currents, according to Schield et al. [1969]: JE are region 1 currents connected to the interplanetary field, JP are currents in the polar ionosphere, JB are region 2 currents and JA are currents of the partial ring current that close the circuit across midnight (the terms "region 1" and "region 2" were only introduced in 1976).

12. A straight current impinging on a uniformly conducting infinite flat sheet creates zero magnetic field underneath. By superposing two such patterns, with opposing straight currents, the property is extended to a current flowing into the (flat) ionosphere and out again.

13. A map of the polar ionosphere, showing the average configuration of Birkeland (field aligned) currents there. Regions where the current enters the ionosphere have dark shading, regions where it flows away from Earth and into space have light shading. From Iijima and Potemra, [1976b]; the origin is at the magnetic pole and the Sun's direction is on top.

14. Plot by Akasofu and Chapman [1963] of the magnetic disturbance associated with a magnetic storm, as observed near the equator (Honolulu) and in the auroral zone (College, in Fairbanks Alaska). The latter is punctuated by many "substorms."

15. The stretching of the Earth's magnetic tail during the "growth phase" which precedes a substorm, from Fairfield and Ness [1970].

16. Schematic view of the formation of a near-Earth neutral line (NENL) and a plasmoid, as proposed by the NENL scenario of substorms.