Darrouzet / De Keyser / Pierrard The Earth's Plasmasphere

A CLUSTER and IMAGE Perspective
1. Auflage 2009
ISBN: 978-1-4419-1323-4
Verlag: Springer
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 296 Seiten

James L. Burch·C. Philippe Escoubet Originally published in the journal Space Science Reviews, Volume 145, Nos 1-2, 1-2. DOI: 10. 1007/s11214-009-9532-7 © Springer Science+Business Media B. V. 2009 The IMAGE and CLUSTER spacecraft have revolutionized our understanding of the inner magnetosphere and in particular the plasmasphere. Before launch, the plasmasphere was not a prime objective of the CLUSTER mission. In fact, CLUSTER might not have ever observed this region because a few years before the CLUSTER launch (at the beginning of the 1990s), it was proposed to raise the perigee of the orbit to 8 Earth radii to make multipoint measu- ments in the current disruption region in the tail. Because of ground segment constraints, this proposal did not materialize. In view of the great depth and breadth of plasmaspheric research and numerous papers published on the plasmasphere since the CLUSTER launch, this choice certainly was a judicious one. The fact that the plasmasphere was one of the prime targets in the inner magnetosphere for IMAGE provided a unique opportunity to make great strides using the new and comp- mentary measurements of the two missions. IMAGE, with sensitive EUV cameras, could for the rst time make global images of the plasmasphere and show its great variability d- ing storm-time. CLUSTER, with four-spacecraft, could analyze in situ spatial and temporal structures at the plasmapause that are particularly important in such a dynamic system.

Autoren/Hrsg.

Darrouzet, Fabien

De Keyser, Johan

Pierrard, Viviane

Inhaltsverzeichnis

1;Contents;4
2;Preface;6
3;Foreword;8
4;CLUSTER and IMAGE: New Ways to Study the Earth's Plasmasphere;11
4.1;Introduction;12
4.2;History of Plasmasphere Data Interpretation;13
4.2.1;Data Interpretation at the Beginning of the Space Age;13
4.2.2;More Refined Space Experiments;16
4.2.3;Radio Probing from Ground and Space;22
4.2.4;Theoretical Understanding;23
4.3;The Quest for a More Global View;24
4.3.1;The Rationale of Global Imaging: Image/EUV Observations;24
4.3.2;Radio Observations in Space with Image/RPI;25
4.3.3;Disentangling Spatial and Temporal Variability with Cluster;27
4.4;New Data Analysis Tools;28
4.4.1;Analysis of Global Images;28
4.4.1.1;Overview of Methods;28
4.4.1.1.1;Removal of Noise and Instrument Artifacts;28
4.4.1.1.2;Photometric Calibration;29
4.4.1.1.3;Three-Dimensional Inversion and Projection on the SM Equatorial Plane;29
4.4.1.1.4;Density Calibration;30
4.4.1.1.5;Comparison of Successive Images;30
4.4.1.1.6;Data Accumulation;31
4.4.1.1.7;Visualization Aids;31
4.4.1.1.8;Correlation with Data from Other Spacecraft or Ground Stations;31
4.4.1.2;Example: A Technique for Determining Plasmaspheric Drifts;32
4.4.1.3;Outlook;34
4.4.2;Interpretation of Remote Sounding and Local Radio Observations;34
4.4.2.1;Remote Sounding;34
4.4.2.2;Local Plasma Observations;36
4.4.3;Classical Gradient Computation and the Curlometer;41
4.4.3.1;Principle;41
4.4.3.2;Error Determination;41
4.4.3.3;Applications;42
4.4.4;Least-Squares Techniques for Gradient Computation;44
4.4.4.1;Principle;44
4.4.4.2;Error Estimates;46
4.4.4.3;Applications;46
4.4.5;Time-Delay Analysis with Multiple Spacecraft;46
4.4.5.1;Method;46
4.4.5.2;Applications;47
4.5;Conclusions and Outlook;47
4.6;Acknowledgements;49
4.7;References;49
5;Plasmaspheric Density Structures and Dynamics: Properties Observed by the CLUSTER and IMAGE Missions;58
5.1;Introduction;59
5.1.1;Before Image and Cluster;59
5.1.2;Image Observations of Density Structures;61
5.1.3;Cluster Observations of Density Structures;62
5.1.4;Outline of the Paper;63
5.2;Sources and Losses in the Plasmasphere;64
5.2.1;The Disturbed Plasmasphere: A New Look at Refilling;64
5.2.2;The Quiet Plasmasphere;66
5.2.3;New Evidence for a Plasmaspheric Wind;68
5.2.4;Erosion of the Plasmasphere;68
5.3;Overall Plasma Distribution and Plasmapause Position;70
5.3.1;Overall View from EUV;70
5.3.2;Plasma Density in the Plasmasphere;70
5.3.3;Overall Density Gradients in the Plasmasphere;71
5.3.4;The Plasmapause Seen by Cluster;73
5.3.4.1;Introduction;73
5.3.4.2;Statistical Study of the Plasmapause Distance;74
5.3.4.3;Plasmapause Dynamics: Position and Velocity;74
5.3.4.4;Statistical Study of the Plasmapause Position and Thickness;75
5.4;Ion Composition;76
5.4.1;Ion Composition from Image;76
5.4.2;Seasonal Variations;77
5.4.3;New Methods of Studying Ion Composition in the Plasmasphere;77
5.4.4;Ion Composition from Cluster;78
5.4.5;Average Ion Mass from Alfvén Waves;79
5.5;Plasmaspheric Plumes;79
5.5.1;Overall Plume Formation;80
5.5.2;Plume Structure and Evolution on Large Scales;81
5.5.2.1;Complicated Structure;81
5.5.2.2;Global Visualisation of a Plume Crossing;83
5.5.3;Plume Structures on Small Scales;84
5.5.4;Statistical Analysis of Plasmaspheric Plumes;86
5.5.5;The Plasmasphere-Ionosphere Connection;87
5.6;Notches;89
5.6.1;Observations of Notches;90
5.6.2;Departures from Corotation;91
5.7;Shoulders, Channels, Fingers, Crenulations;93
5.8;Small-Scale Density Irregularities;94
5.8.1;Earlier Work;94
5.8.1.1;Field-Aligned Density Irregularities;94
5.8.1.2;Irregular Density Structures in the Outer Plasmasphere;95
5.8.2;Remote Sensing of Density Irregularities by the RPI Instrument;95
5.8.2.1;Comments on RPI Observations;95
5.8.2.2;Interpretation of RPI Observations in Terms of Density Structure;96
5.8.3;In situ Observations of Small-Scale Density Structures;97
5.8.3.1;Morphology;97
5.8.3.2;Dynamics;98
5.8.3.3;Occurrence;99
5.9;Conclusion;99
5.9.1;Sources and Losses in the Plasmasphere;99
5.9.2;Overall Plasma Distribution and Ion Composition;100
5.9.3;Plasmaspheric Plumes;100
5.9.4;Density Structures at Smaller Scales;101
5.9.5;Perspectives;102
5.10;Acknowledgements;102
5.11;References;103
6;Electric Fields and Magnetic Fields in the Plasmasphere: A Perspective from CLUSTER and IMAGE;110
6.1;Introduction;111
6.1.1;Whistler Measurements to Derive Convection;111
6.1.1.1;The Whistler Method of Measuring Cross-L Plasma Drifts;112
6.1.1.2;Whistler Estimates of the Ey Electric Field Component Near Dusk;114
6.1.1.3;Measurements on Whistler-Mode Transmitter Signals;114
6.1.2;Cluster and Image Achievements;115
6.2;Inner Magnetospheric Electric Fields Measured by CLUSTER;116
6.2.1;EDI Onboard Cluster;117
6.2.2;Inner Magnetospheric Electric Fields;117
6.2.2.1;Case Studies;117
6.2.2.2;Statistical Studies on IMF BZ Dependence;119
6.2.2.3;Statistical Studies on IMF BY Dependence;121
6.2.3;Summary;122
6.3;Inner Magnetospheric Electric Fields From Plasmasphere Images;122
6.3.1;Technique for Deducing Electric Fields From Image;122
6.3.2;Phenomenology of the Erosion Process;122
6.3.3;Internal Magnetospheric Electric Fields;123
6.4;SAPS Electric Fields;124
6.4.1;DMSP and Image Observation;124
6.4.2;Multi-Spacecraft Observations of SAID: A Cluster Perspective;125
6.4.2.1;SAID Electric Field;125
6.4.2.2;SAID Field-Aligned Current;127
6.5;Spatial Gradients of the Magnetic Field in the Plasmasphere from CLUSTER;127
6.5.1;Datasets and Analysis Technique;128
6.5.2;A Typical Plasmasphere Crossing;128
6.5.3;Summary and Conclusions;131
6.6;Summary and Outlook;132
6.7;Acknowledgements;134
6.8;References;134
7;Advances in Plasmaspheric Wave Research with CLUSTER and IMAGE Observations;139
7.1;Introduction;140
7.2;CLUSTER and IMAGE Wave Instrumentation;142
7.2.1;Cluster Wave Instruments;142
7.2.2;Image Wave Related Phenomena Instruments;142
7.3;Kilometric Continuum;143
7.3.1;Previous Observations;143
7.3.2;Image Observations;144
7.3.3;Conclusions;147
7.4;Non-Thermal Continuum;149
7.4.1;Cluster Observations;149
7.4.1.1;Assets of the CLUSTER Mission;149
7.4.1.2;Typical Spectral Signatures;150
7.4.2;Analysis;153
7.4.2.1;Beam Stability;153
7.4.2.2;Beam Geometry;153
7.4.3;Interpretation;156
7.4.3.1;Main NTC Form (Quasi Equatorial Sources);156
7.4.3.1.1;Close up View on Sources;156
7.4.3.1.2;Propagation Effects;157
7.4.3.2;Wide Banded NTC Emissions;157
7.5;Z-Mode;158
7.5.1;Active Z-Mode Experiments in Space Plasmas;158
7.5.2;Z-Mode Sounding from Image;159
7.5.2.1;Ducted Echoes and the Z-Mode Propagation ``Cavity'';160
7.5.2.2;Remote Sensing of Density Profiles Along the Geomagnetic Field Lines Above IMAGE;162
7.5.2.3;Remote Sensing of Plasma Composition Along the Geomagnetic Field Lines;163
7.5.3;Additional Diagnostics Uses of Z-Mode Echoes;164
7.5.3.1;Non-Ducted or ``Direct'' Earthward Propagating Z-Mode Echoes;164
7.5.3.2;Diagnostic Uses of Direct Z-Mode Echoes;164
7.5.3.3;Scattered Z-Mode Echoes;164
7.5.3.4;Diagnostic Uses of Scattered Z-Mode Echoes;165
7.6;Whistler-Mode Soundings at Altitudes Below 5000 km;166
7.6.1;Spreading of RPI Whistler-Mode Echoes in Time Delay;166
7.6.2;Examples of Magnetospherically Reflected and Specularly Reflected Whistler-Mode Echoes;167
7.6.3;Specularly Reflected Whistler-Mode Echoes;167
7.6.4;Magnetospherically Reflected Whistler-Mode Echoes and the Lower Hybrid Resonance;168
7.6.5;The Diagnostic Potential of Magnetospherically Reflected and Specularly Reflected Whistler-Mode Echoes;168
7.7;Proton Cyclotron Echoes and a New Resonance;169
7.7.1;The fce+ Echo;169
7.7.2;The fce+ Resonance;170
7.7.3;Whistler-Mode Proton Cyclotron Echoes;170
7.7.4;Comments on Physical Mechanisms of Proton Cyclotron Echoes;172
7.8;Chorus;173
7.8.1;Observations of Whistler-Mode Chorus Emissions by Cluster;173
7.8.2;Position and Size of the Chorus Source Region;173
7.8.3;Propagation of Chorus From its Source Region;174
7.9;Hiss;176
7.9.1;Plasmaspheric Hiss;176
7.9.1.1;Impact on the Radiation Belts;177
7.9.1.2;Origin of Plasmaspheric Hiss;177
7.9.2;Mid-Latitude Hiss;178
7.9.2.1;Mid-Latitude Hiss and Auroral Hiss;178
7.9.2.2;Source Location and Generation Mechanism;179
7.9.2.3;Geomagnetic Activity Impact;180
7.10;Equatorial Noise;180
7.10.1;Introduction;180
7.10.2;Cluster Observations;181
7.10.3;Generation Mechanism of Equatorial Noise and its Effects;183
7.11;ULF Resonances;183
7.11.1;Historical Description;183
7.11.2;Image Observations;184
7.12;Conclusion;185
7.13;Acknowledgements;186
7.14;References;187
8;Recent Progress in Physics-Based Models of the Plasmasphere;194
8.1;Introduction;195
8.2;The Fluid Approach;196
8.2.1;Inner Magnetospheric Electric Potential;196
8.2.2;Plasmasphere-Ionosphere Coupling;201
8.2.3;Plasmasphere-Magnetosphere Coupling;203
8.3;The Kinetic Approach;205
8.3.1;Plasmapause Formation;205
8.3.2;Plasmaspheric Wind;206
8.3.2.1;The Role of Quasi-Interchange Modes;208
8.3.2.2;Testing the Instability Criteria of Quasi-Interchange Modes in the Plasmasphere;208
8.3.2.3;Implications of a Plasmaspheric Wind and Future Refinements;209
8.3.3;Transport of Plasmaspheric Material Caused by Ultra Low Frequency Waves;209
8.3.4;Electric Field in Equilibrium Theory;212
8.3.5;Stationary Density Distribution in the Plasmasphere;212
8.3.5.1;The Exospheric Equilibrium Density Distributions;214
8.3.5.2;Physics Model Constrained by Empirical Data;216
8.3.6;Kinetic Process of Plasmaspheric Refilling;217
8.3.6.1;Coulomb Collisions;217
8.3.6.2;Monte Carlo Simulations;218
8.4;Comparison Between MHD and Kinetic Approaches;219
8.4.1;Time Dependent Models for Field-Aligned Plasma Density Distribution;220
8.4.2;Time Dependent Refilling Model;220
8.4.3;Other Models of the Plasmasphere;221
8.5;Conclusions;222
8.6;Acknowledgements;223
8.7;References;223
9;Augmented Empirical Models of Plasmaspheric Density and Electric Field Using IMAGE and CLUSTER Data;231
9.1;Introduction;232
9.2;Empirical Equatorial Density Models;233
9.3;Field-Aligned Density Distributions for Plasmasphere and Plasma Trough;235
9.3.1;Field Line Dependence of Electron Density from in Situ Data;235
9.3.2;Field Line Dependence of Mass Density Based on Spacecraft Observations of Alfvén Frequencies;235
9.3.3;Event-Driven Density Model;236
9.3.4;Field-Aligned Dependence from Image RPI Measurements;237
9.4;Field-Aligned Density Distributions in the Polar Cap;244
9.5;Empirical Models of Electric Field;246
9.5.1;The Corotation Electric Field;246
9.5.2;Empirical Convection Electric Field Models;246
9.5.2.1;Volland-Stern's and Maynard-Chen's (VSMC) Convection Electric Field Model;247
9.5.2.2;McIlwain's E5D Convection Electric Field Model;247
9.5.2.3;Weimer's Convection Electric Field Model;248
9.5.2.4;Inner Magnetospheric Electric Field (UNH-IMEF) Model;249
9.5.3;Influence of Electric Field Models on the Plasmapause Position Modeling;253
9.6;Summary;254
9.7;Acknowledgements;255
9.8;References;255
10;Index;262
11;Bibliography;268