Multipoint Magnetospheric Measurements

Advances in Space Research, 8(9)
Edited by: C.T. Russell
464pp, Pergamon Press, Oxford 1988.

Table of Contents

PREFACE

At the 27th Plenary Meeting of COSPAR held in Espoo, Finland, a symposium on Multipoint Measurements of Magnetospheric Processes was convened by the International Scientific Commission D. Topics discussed included auroral processes, in particular the insight gained from the recent Viking mission, substorm phenomena, the shock and foreshock, the solar wind-magnetosphere interaction, the magnetopause and reconnection, magnetosphere-ionosphere interactions, the physics of the inner magnetosphere and various wave processes. Measurements from both spacecraft and ground-based instruments were included. Theory was included as it pertained to the interpretation of multipoint measurements. The presentations consisted of roughly equal time devoted to invited and contributed papers. Not all abstracts submitted were accepted for presentation and not all papers presented at the symposium were accepted for publication in this volume. The scientific program was organized with the able advice of L. P Block, O. de la Beaujardiere, E. W. Hones, G. Paschmann and O. L. Vaisberg for whose help the editor is extremely grateful. The response of the presenters to the editor's appeal for manuscripts has been high and the resulting volume presents a good summary of the deliberations of the conference.

This volume contains a large number of results obtained only recently. Notable among these results are observations from Viking, EXOS-C, Eiscat and the Greenland magnetometer chain. Older missions such as IMP-8, Prognoz, ISEE and DE continue to provide new insight despite their age and in some cases their demise. The quality of submittals has been very high. The authors have spent much time on these papers with the expectation, shared by the editor, that this volume will be extremely useful to the participants in the ISTP program, especially those with instrumentation on CRRES, Wind, Polar, Geotail, Cluster and any associated spacecraft. We hope that these papers can help guide the measurement strategies and scientific objectives of these participants. This volume also contains many gems for the careful reader such as the fact that a man with two watches is unsure of the time. There are discussions of how one group learned to bolt their instruments careful to their rocket and of how long it takes for the snow to melt downrange at ESRANGE.

Chapter 1 treats auroral processes and highlights the new results obtained with the Viking spacecraft. The increased time resolution of the Viking imager has revealed, for example, that there are large scale brightenings of the aurora on time scales of less than one minute and the high spatial resolution combined with the improved temporal resolution shows the expected control of auroral motions by the By component of the interplanetary magnetic field suggesting that the Viking imagers are detecting the footprints of newly connected flux tubes Ground based instrumentation too can be used to study the influence of the IMF on the aurora and P. E. Sandholt describes such a study of the polar cusp and cleft. The Viking program was coordinated with rocket aircraft and radar campaigns. I. Sandahl describes two rocket shots during passages of the Viking spacecraft while H. Carlson describes coordinated aircraft flights. Lest we begin to believe that the only space based auroral cameras are on Viking, P. Sandholt and coworkers and D. H. Brautigam remind us that useful results can also be derived from those workhorse satellite DMSP/F6 and DMSP/F7.

Chapter 2 moves us into the realm of substorms which are so intimately connected to the night time auroral processes. R. L. McPherron shows us how strongly the magnetospheric current systems are controlled by the interplanetary magnetic field. I. Daglis and coworkers and R. E. Lopez and coworkers examine the behavior of energetic ions at the time of substorms. One very interesting result of the Lopez study is that even at 8 RE substorm effects tend to propagate radially outward rather than inward. D. H. Fairfield reviews multipoint measurements of tail dynamics. He too finds little evidence for inward propagation in the inner magnetosphere, but he feels that the observed time delays are consistent with azimuthal propagation. Additional studies of the dynamics of the tail can be found in the following articles by D. N. Baker and colleagues and E. W. Hones and colleagues. V. A Sergeev and coworkers use ground-based Riometer and magnetometer data to infer the thickness of the current sheet through its scattering of energetic electrons. They find that the current sheet at 9 "RE" can be as thin as 0.l "RE" Comparing DE imaging data with ISEE-l plasma data E. W. Hones concludes that longitudinal advances of the aurora are due to lengthening of the neutral sheet across the tail. W. Lennartsson has also examined the plasma sheet carefully but at times when the IMF was northward. At these times the proton and alpha particle density is highest and strongly correlated with the solar wind density. This suggests that at quiet times the plasma sheet is most strongly coupled to the solar wind but at disturbed times (when Bz is southward) coupling to the ionosphere also occurs.

Chapter 3 moves the reader out of the magnetosphere into the solar wind for a discussion of bow shock and foreshock phenomena. The first article in this chapter (by myself) reviews precursor waves and upstream waves in front of interplanetary shocks which are generally weaker than planetary bow shocks. An examination of the waves upstream of the planetary bow shock reveals that the form of the upstream waves may depend more on the direction of the field and flow than had been previously appreciated. M. Thomsen follows with a review of the progress in understanding the bow shock from multisatellite data. Not only did these studies make it possible to measure shock thickness and velocity for the first time but they also led to the understanding of a variety of the physical processes occurring in shocks. The chapter ends with three papers discussing shock motion. While generally the shock moves back and forth over the spacecraft in response to the solar wind pressure changes as discussed by Z. Nemecek and coworkers, there are exceptions. As shown by G. Zastenker and colleagues, since the pressure pulses propagate with the solar wind, ripples start at the nose and propagate tailward. While this is expected, M. Thomsen and co-authors report a rather unexpected motion. When multiple spacecraft are aligned with the flow velocity above the nose of the shock, and the IMF is nearly aligned with the flow upstream waves appear to steepen into shocks and the shock front seems to repeatedly cross the upstream spacecraft first rather than move back and forth across the two spacecraft. This observation shows that the upstream waves and the quasi-parallel bow shock are intimately linked.

Chapter 4, entitled Solar Wind Interactions, covers a variety of topics that could not be more specifically described. The principal focus of the AMPTE mission was the generation of clouds of Lithium and Barium ions in the solar wind and tail of the Earth to see both how the ambient plasma interacted with the clouds and how the ions were transported. Studies of the interaction with the cloud were spectacularly successful but no ions were detected in the inner magnetosphere as a result of these releases. A novel instrument on the ISEE-1 and 2 spacecraft, a propagation experiment to determine the integrated density between the two spacecraft is reviewed by C. Harvey and colleagues. Cross correlations of the density and the magnetic field data of the spacecraft allows the identification of wave modes. Leakage of energetic particles out of the magnetosphere has also become a topic of great concern since these leaked particles may contribute to the population of particles seen upstream from the Earth and usually attributed to Fermi-acceleration and bow shock reflection. This process is treated by both J. Blake and coworkers and D. Sibeck and R. McEntire. At least near the magnetopause, the leakage process seems to be the dominant source of energetic particles. The final paper in this chapter by M. Freeman and D. Southwood correlates fluctuations in the IMF with fluctuations in the magnetosheath. While most fluctuations in the magnetosheath are convected counterparts of solar wind features, flux transfer events appear to have no counterpart in the solar wind.

Chapter 5 discusses the magnetopause and reconnection. As R. Elphic discusses, the dual ISEE 1 and 2 spacecraft were critical to our present day understanding of the magnetopause. This boundary is thicker than initially expected but it can contain rather thin structures within it. Reconnection has been conclusively demonstrated in both quasi-steady and temporally varying forms. Surface oscillations of the magnetopause can be caused by pressure fluctuations or by reconnection, but there is little evidence for the Kelvin-Helmholtz instability. One of the advantages of the ISEE-l and 2 satellites is that they allow temporal profiles to be translated into spatial profiles allowing comparison with theory as M. Heyn and colleagues show. Pu Song and coworkers use these same satellites to analyze the motion of the magnetopause while C. Farrugia and colleagues review observations of Flux Transfer Events both with ISEE and AMPTE. They conclude that FTE's are in fact associated with patchy or sporadic reconnection. X. Zhu and colleagues report on a very unusual FTE event with a normal component which is almost as strong in the normal direction as the total field strength. B. Sonnerup follows with a discussion of the possible tests of FTE theories. The planned Cluster spacecraft will be very useful in this regard. M. Dunlop and coworkers then discuss how multipoint magnetometer data from the Cluster spacecraft can be used.

Chapter 6 covers magnetosphere-ionosphere interactions from those associated with the magnetopause current system to those associated with auroral substorms. M. Lockwood and S. Cowley begin the chapter with a discussion of momentum transfer to the dayside ionosphere as studied with the EISCAT radar. They conclude that only newly opened flux tubes impart significant momentum to the ionosphere. L. J. Lanzerotti follows with a discussion of the ground magnetic signature of this coupling. A pair of papers led by E. Friis-Christensen and M. McHenry examine magnetic variations in the polar cleft region which are shown to be caused by traveling convection vortices. These vortices appear to be caused by surface waves on the magnetopause and not associated with FTE's. W. Hughes reviews field-aligned current systems. He finds that the classic Iijima and Potemra pattern is seen only about 25% of the time in the middle magnetosphere. Y. Kamide reviews how to deduce the 3-dimensional current system in the magnetosphere from ground based data. H. E. Spence and coworkers compare the field-aligned currents in the distant magnetosphere with those seen at low a altitudes with MAGSAT. Finally P. Rothwell and coworkers discuss their model for the substorm breakups on closed field lines.

Chapter 7 has the rather non-specific title, The Inner Magnetosphere. This chapter provides a home for those papers that describe processes occurring well within the magnetosphere but not necessarily associated with substorms and not clearly directly driven by the solar wind interaction. J. Burch leads off with a discussion of simultaneous plasma data obtained by DE 1 and 2. These satellites have been used to show the temporal stability of inverted-V events and infer the existence of potential drops along field lines. The following paper examines some of the results obtained in conjunction with the EXOS-C or OHZORA satellite. T. Mukai and colleagues examine both spike-like precipitation in the polar cap and acceleration of inverted-V particles. D. Weimer examines times of magnetic conjugacy on DE-1 and 2 and finds that the large scale fields are similar but that there is more fine scale field at higher altitudes. Finally D. Baker discusses multipoint measurements of energetic particles. These particles are most sensitive to the global magnetic geometry and less sensitive to local electric field effects.

The last chapter discusses waves, both ULF and plasma waves. J. Samson begins with a discussion of how to use ground based measurements of ULF waves to infer their properties in the magnetosphere. V. Troitskaya and O. Bolshakova then review how such waves can be used to provide diagnostics of both the conditions in the solar wind and the state of the magnetosphere. Then we move into the magnetosphere itself with a review by K. Takahashi on multisatellite observations of ULF waves. He shows that compressional Pc 5 waves are most consistent with the drift-mirror instability. N. Lin and coworkers discuss how to remove some of the ambiguities in studies of waves in the magnetosphere by using measurements of ions at multiple energies. H. J. Singer and colleagues discuss the relationship of magnetic pulsations seen on the ground to plasma sheet thickening seen in space. J. R. Sharber and colleagues provide a change in frequency range to VLF frequencies, reporting on electrostatic waves seen in association with field aligned electron beams on DE 1. This paper is followed by a rapid change in location to a study of kilometric radiation at Jupiter by D. Jones and Y. Leblanc. Finally, J. Pincon and F. Lefeuvre discuss how to treat homogeneous field turbulence using multiple point data.

This symposium is dedicated to the memory of Wolfgang Studemann who was killed on the way to last December's meeting of the American Geophysical Union. As detailed in the accompanying In Memoriam by V. Vasylinnas, Wolfgang was in his prime when he was struck down. Tragedy visited once again when on July 17, F. L. Scarf, one of the leading researchers and planners of the space plasma physics program died in Moscow on his way to attend the meeting. We will miss them both dearly.

In closing I would like to thank the referees who worked hard reviewing the papers at the meeting and whose efforts thus permitted the timely production of this volume: R. Elphic, Y. Kamide, M. G. Kivelson, M. Lockwood, I. Sandahl, M. Scholer, D. G. Sibeck, and P. Tanskanen. The referees were aided in this evaluation of the papers by the chairmen of the sessions who are owed additional thanks for their keeping the sessions to schedule while permitting adequate discussion time, always a delicate balance to strike. The sessions were chaired by D. N. Baker, L. P. Block, E. W Hones, L. J. Lanzerotti, R. L. McPherron, A Nishida, B. U. O. Sonnerup and D. J. Southwood. I would also like to thank Z. Niemirowicz and his COSPAR staff for once again providing excellent support for the symposium and to thank the local organizers for ably managing the facilities and supporting the every need of the presenters. Finally I am extremely grateful for the efforts of my own staff in particular P. Rowe, C. Bouwer and S. Suk who assisted with correspondence prior to the conference and after it, and M. Ishiwata who helped me repair manuscripts and artwork as required. All this assistance made my job much easier.

C T Russell
Institute of Geophysics and Planetary Physics
Department of Earth and Space Sciences
University of California, Los Angeles
October 1988

CONTENTS

Preface

Page 5: In Memoriam Wolfgang Studemann (1940-1987); V. M. Vasyliunas

Chapter 1--AURORAL PROCESSES

Page 9: Correlative Studies Using the Viking Imagery; J. S. Murphree and R. D. Elphinstone

Page 21: IMF Control of Polar Cusp and Cleft Auroras; P. E. Sandholt

Page 35: Coordinated Viking and Sounding Rocket Studies; I. Sandahl

Page 49: Satellite, Airborne and Radar Observations of Auroral Arcs; H. C. Carlson, Jr, E. J. Weber, L. P. Block and Sunanda Basu

Page 59: Polar Cleft Structure and Dynamics in the Prenoon Sector; P. E. Sandholt, B. Jacobsen, B. Lybekk, A. Egeland, C.-I. Meng, P. T. Newell, F. J. Rich and E. J. Weber

Page 65: The IMF Bz and Solar Wind Speed Dependence for Precipitating lon Hemispheric Energy Flux; D. H. Brautigam, M. S. Gussenhoven and D. A. Hardy

Chapter 2--SUBSTORMS

Page 71: IMF Control of Geomagnetic Activity; R. L. McPherron, D. N. Baker, L. F. Bargatze, C. R. Clauer and R. E. Holzer

Page 87: Observations of the Ion Distribution in the Nightside Magnetosphere During Substorm-Associated Dropout Events; I. A. Daglis, G. Kremser, W. Studemann, B. Wilken, G. Gloeckler, D. C. Hamilton and F. M. Ipavich

Page 91: The Radial and Longitudinal Propagation Characteristics of Substorm Injections; R. E. Lopez, D. N. Baker, A. T. Y. Lui, D. G. Sibeck, R. D. Belian, R. W. McEntire, T. A. Potemra and S. M. Krimigis

Page 97: Multipoint Measurements of Magnetotail Dynamics; D. H. Fairfield

Page 109: On the Energetic Particle Dynamics in the Distant Magnetotail; A. E. Antonova, O. R. Griroryan and V. G. Stolpovsky

Page 113: The CDAW-8 Substorm Event on 28 January 1983: A Detailed Global Study; D. N. Baker, J. D. Craven, R. C. Elphic, D. H. Fairfield, L. A. Frank, H. J. Singer, J. A. Slavin , I. G. Richardson, C. J. Owen and R. D. Zwickl

Page 119: Study of a Substorm on May 4, 1986; E. W. Hones, R. D. Elphinstone, A. B. Galvin, P. R. Higbie and J. S. Murphree

Page 125: Current Sheet Thickness in the Near-Earth Plasma Sheet During Substorm Growth Phase as Inferred from Simultaneous Magnetotail and Ground-Based Observations; V. A. Sergeev, P. Tanskanen, K. Mursula, A. Korth and R. C. Elphic

Page 129: Association of Plasma Sheet Variations with Auroral Changes During Substorms; E. W. Hones, Jr

Page 135: Comparison of Plasma Sheet Ion Composition with the IMF and Solar Wind Plasma; W. Lennartsson

Page 139: Characteristics of Ps6 Pulsations During the CDAW-6 Substorm; G. I. Korotova and A. N. Zaitzev

Chapter 3--SHOCK AND FORESHOCK

Page 147: Multipoint Measurements of Upstream Waves; C. T. Russell

Page 157: Multi-Spacecraft Observations of Collisionless Shocks; M. F. Thomsen

Page 167: Dynamics of the Earth's Bow Shock Position; Z. Nemecek, J. Safrankova and G. Zastenker

Page 171: Bow Shock Motion with Two-Point Observations: Prognoz 7, 8 and ISEE 1, 2; Prognoz 10 and IMP 8; G. N. Zastenker, C. T. Russell, H. S. Bridge, A. Lazarus, V. N. Smirnov, Z. Nemecek and J. Safrankova

Page 175: ISEE Studies of the Quasi-Parallel Bow Shock; M. F. Thomsen, J. T. Gosling and C. T. Russell

Chapter 4--SOLAR WIND INTERACTIONS

Page 181: Low Frequency Magnetic Wave Spectra Associated with the AMPTE Barium Release of 27 December 1984; D. G. Gleaves, D. J. Southwood, M. W. Dunlop and W. A. C. Mier-Jedrzejowicz

Page 185: Results from the ISEE Propagation Density Experiment; C. C. Harvey, L. Celnikier and D. Hubert

Page 197: The 8 February 1986 Magnetospheric Compression Event: Observations of Simultaneous Magnetospheric Leakage and Specularly Reflected Solar Wind Ions; J. B. Blake, R. D. Belian, D. R. Croley, J. F. Fennell, G. Gloeckler, D. C. Hamilton and D. N. Baker

Page 201: Multiple Satellite Observations of Leakage of Particles from the Magnetosphere D. G. Sibeck and R. W. McEntire

Page 217: The Correlation of Variations in the IMF with Magnetosheath Field Variations; M. P. Freeman and D. J. Southwood

Chapter 5--MAGNETOPAUSE AND RECONNECTION

Page 223: Multipoint Observations of the Magnetopause: Results from ISEE and AMPTE; R. C. Elphic

Page 239: Energy Flow Inside a Reconnection Layer Containing Slow Shocks; M. F. Heyn, R. P. Rijnbeek, H. K. Biernat, V. S. Semenov, C. J. Farrugia, D. J. Southwood, G. Paschmann, N. Sckopke and C. T. Russell

Page 245: Multi-Spacecraft Observations of Magnetopause Surface Waves: ISEE 1 and 2 Determinations of Amplitude, Wavelength and Period; Pu Song, R. C. Elphic and C. T. Russell

Page 249: Observations of Flux Transfer Events; C. J. Farrugia, D. J. Southwood and S. W. H. Cowley

Page 259: An ISEE-1/2 Spacecraft Study of an Unusual Flux Transfer Event; X. M. Zhu, M. G. Kivelson, R. J. Walker, C. T. Russell, M. F. Thomsen and D. J. McComas

Page 263: Experimental Tests of FTE Theories; B. U. O. Sonnerup

Page 273: Analysis of Multipoint Magnetometer Data; M. W. Dunlop, D. J. Southwood, K.-H. Glassmeier and F. M. Neubauer

Chapter 6--MAGNETOSPHERE-IONOSPHERE INTERACTIONS

Page 281: Observations at the Magnetopause and in the Auroral Ionosphere of Momentum Transfer from the Solar Wind; M. Lockwood and S. W. H. Cowley

Page 301: Conjugate Spacecraft and Ground-Based Studies of Hydromagnetic Phenomenon Near the Magnetopause; L. J. Lanzerotti

Page 311: Irregular Magnetic Pulsations in the Polar Cleft Caused by Traveling Ionospheric Convection Vortices; E. Friis-Christensen, S. Vennerstrom, C. R. Clauer and M. A. McHenry

Page 315: Observations of Ionospheric Convection Vortices: Signatures of Momentum Transfer; M. A. McHenry, C. R. Clauer, E. Friis-Christensen and J. D. Kelly

Page 321: Multisatellite Observations of Field-Aligned Current Systems; W. J. Hughes

Page 333: Inferring Field-Aligned Current Systems and Other Ionospheric Quantities from Ground-Based Arrays: A Review; Y Kamide

Page 343: Comparison of Field-Aligned Currents at Ionospheric and Magnetospheric Altitudes; H. E. Spence, M. G. Kivelson and R. J. Walker

Page 347: Substorm Breakup on Closed Field Lines; P. L. Rothwell, L. P. Block, M. B. Silevitch and C. -G. Falthammar

Chapter 7--INNER MAGNETOSPHERE

Page 353: Simultaneous Plasma Observations with DE-1 and DE-2; J. L. Burch

Page 363: EXOS-C (OHZORA) Observations of Polar Cap Precipitations and Inverted V Events; T. Mukai, N. Kaya, T. Obara, M. Kitayama and A. Nishida

Page 373: Auroral E-Fields from DE-I and -2 at Magnetically Conjugate Points; D. R. Weimer

Page 385: Multipoint Measurements of Energetic Particles in the Magnetosphere; D. N. Baker

Chapter 8--WAVES

Page 399: ULF Wave Studies Using Ground-Based Arrays; J. C. Samson

Page 413: Diagnostics of the Magnetosphere Using Multipoint Measurements of ULF-Waves; V A. Troitskaya and O. V. Bolshakova

Page 427: Multisatellite Studies of ULF Waves; K. Takahashi

Page 437 Multi-Point Measurements of ULF Wave Phases Using a Multi-Channel Energetic Ion Detector; N. Lin, M. G. Kivelson, R. L. McPherron, D. J. Williams and T. A. Fritz

Page 443: Multipoint Measurements from Substorm Onset to Recovery: The Relation between Magnetic Pulsations and Plasma Sheet Thickening; H. J. Singer, E. W. Hones, Jr and T. J. Rosenberg

Page 447: Plasma Waves Associated with Diffuse Auroral Electrons at Mid-Altitudes; J. R. Sharber, J. D. Menietti, H. K. Wong, J. L. Burch, D. A. Gurnett, J. D. Winningham and P. J. Tanskanen

Page 453: Analysis of Jovian Kilometric Radiation Simultaneously Observed by Voyagers 1 and 2; D. Jones and Y. Leblanc

Page 459: Characterization of a Homogeneous Field Turbulence from Multlpolnt Measurements; J. L. Pincon and F. Lefeuvre

Page 463: Author Index


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