Magnetoseismology: Ground–based Remote Sensing of Earths Magnetosphere

This book provides a comprehensive account of magnetoseismology - the tool to monitor space weather.  Written by researcher on the forefront of this field, it conveys the physics behind the phenomena and the methods to detect and investigate them, the relevance to communication, power supply and many other critical systems.  In addition, it provides computational codes for analysis and evaluation.

Preface IX

Color Plates XI

1 Introduction 1

1.1 Purpose of This Book 1

1.2 The Solar Wind 1

1.3 Fluctuations in the Solar Wind 5

1.4 Early Observations of Geomagnetic Variations 7

1.5 Properties of Geomagnetic Variations 8

2 The Magnetosphere and Ionosphere 13

2.1 The Geomagnetic Field 13

2.2 Structure of Earth’s Magnetosphere 19

2.3 Magnetospheric Current Systems 24

2.3.1 Magnetopause Current 24

2.3.2 Tail Current and Reconnection 24

2.3.3 Ring Current 26

2.3.4 Field-Aligned Currents 26

2.3.5 Ionospheric Currents 27

2.4 The Radiation Belts 28

2.5 The Inner Magnetosphere 30

2.6 Formation and Properties of the Ionosphere 33

2.7 Geomagnetic Disturbances 38

2.8 Space Weather Effects 42

3 ULF Plasma Waves in the Magnetosphere 45

3.1 Basic Properties of a Plasma 45

3.2 Particle Motions 47

3.2.1 Motions of Isolated Charged Particles 47

3.2.2 First Adiabatic Invariant 49

3.2.3 Second Adiabatic Invariant 50

3.2.4 Third Adiabatic Invariant 51

3.3 Low-Frequency Magnetized Plasma Waves 52

3.3.1 Equations of Linear MHD 53

3.3.2 The Wave Equation 54

3.4 The Shear Alfven Mode in a Dipole Magnetic Field 54

3.4.1 Toroidal Oscillation of Field Lines 54

3.5 MHD Wave Mode Coupling in One Dimension 56

3.6 An Alternative Derivation of the Plasma Wave Equation, from Electromagnetism 61

4 Sources of ULF Waves 63

4.1 Introduction 63

4.2 Exogenic Sources 65

4.3 Boundary Instabilities 71

4.4 Field Line Resonances 74

4.5 Cavity and Waveguide Modes 79

4.6 Spatially Localized Waves 81

4.7 Ion Cyclotron Waves 84

5 Techniques for Detecting Field Line Resonances 87

5.1 Introduction 87

5.2 Variation in Spectral Power with Latitude 90

5.3 Variation of Phase with Latitude 91

5.4 Wave Polarization Properties 92

5.5 Spectral Power Difference and Division 95

5.6 Single Station H/D 95

5.7 Cross-Phase from Latitudinally Separated Sensors 98

5.8 Using ULF Wave Polarization Properties 100

5.9 Automated Detection Algorithms 103

6 Ground-Based Remote Sensing of the Magnetosphere 107

6.1 Estimating Plasma Mass Density 107

6.2 Travel Time Method of Tamao 109

6.3 Determining Electron Density 113

6.4 Verification of Ground-Based Mass Density Measurements 116

6.5 Determining Ion Concentrations 121

6.6 Field-Aligned Plasma Density 122

6.7 Plasma Density at Low Latitudes 126

6.8 Plasma Density at High Latitudes 128

7 Space Weather Applications 133

7.1 Magnetospheric Structure and Density 133

7.2 Plasmapause Dynamics 134

7.3 Density Notches, Plumes, and Related Features 139

7.4 Refilling of the Plasmasphere 145

7.5 Longitudinal Variation in Density 148

7.6 Solar Cycle Variations in Density 150

7.7 Determining the Open/Closed Field Line Boundary 152

7.8 Determining the Magnetospheric Topology at High Latitudes 153

7.9 Wave–Particle Interactions 155

7.10 Radial Motions of Flux Tubes 160

8 ULF Waves in the Ionosphere 163

8.1 Introduction 163

8.2 Electrostatic and Inductive Ionospheres 164

8.3 ULF Wave Solution for a Thin Sheet Ionosphere 167

8.4 ULF Wave Solution for a Realistic Ionosphere 171

8.5 FLRs and the Ionosphere 177

8.6 Remote Sensing ULF Electric Fields in Space 181

8.7 Quarter-Wave Modes 183

8.8 Detection of ULF Waves in the Ionosphere 186

8.9 Consequences for Radio Astronomy 192

9 Magnetoseismology at Other Planets and Stars 195

9.1 Magnetoseismology at Other Planets 195

9.2 Magnetoseismology of the Solar Corona 198

9.3 Introduction to Helioseismology and Asteroseismology 200

9.4 Field Line Resonances at Other Stars 204

Appendix A 207

Appendix B 211

References 215

Index 243