Preface ......................................................... v
I Collisionless Shock Theory ................................... 1
1 Introduction ................................................. 3
2 The Shock Problem ............................................ 7
2.1 A Cursory Historical Overview ........................... 7
2.1.1 The Early History ................................ 7
2.1.2 Gasdynamic Shocks ................................ 9
2.1.3 Realising Collisionless Shocks .................. 11
2.1.4 Early Collisionless Shock Investigations ........ 13
2.1.5 Three Decades of Exploration: Theory and
Observation ..................................... 15
2.1.6 The Numerical Simulation Age .................... 18
2.2 When Are Shocks? ....................................... 23
2.3 Types of Collisionless Shocks .......................... 26
2.3.1 Electrostatic Shocks ............................ 27
2.3.2 Magnetised Shocks ............................... 27
2.3.3 MHD Shocks ...................................... 29
2.3.4 Evolutionary .................................... 30
2.3.5 Coplanarity ..................................... 31
2.3.6 Switch-On and Switch-Off Shocks ................. 32
2.4 Criticality ............................................ 34
2.5 Remarks ................................................ 36
References .................................................. 38
3 Equations and Models ........................................ 45
3.1 Wave Steeping .......................................... 45
3.1.1 Simple Waves: Steeping and Breaking ............. 45
3.1.2 Burgers' Dissipative Shock Solution ............. 48
3.1.3 Korteweg-de Vries Dispersion Effects ............ 50
3.1.4 Sagdeev's Pseudo-potential ...................... 52
3.2 Basic Equations ........................................ 54
3.2.1 Kinetic Plasma Equations ........................ 55
3.2.2 Conservation Laws ............................... 57
3.3 Rankine-Hugoniot Relations ............................. 59
3.3.1 Explicit MHD Shock Solutions .................... 61
3.3.2 Perpendicular Shocks ............................ 63
3.3.3 Parallel Shocks ................................. 64
3.3.4 High Mach Numbers ............................... 65
3.4 Waves and Instabilities ................................ 66
3.4.1 Dispersion Relation ............................. 66
3.4.2 The MHD Modes - Low-β Shocks .................... 71
3.4.3 Whistlers and Alfven Shocks ..................... 75
3.4.4 Instabilities ................................... 80
3.4.5 "Transport Ratios" .............................. 87
3.5 Anomalous Transport .................................... 90
3.5.1 Electrostatic Wave Particle Interactions ........ 91
3.5.2 Anomalous Resistivity .......................... 102
3.5.3 Shock Particle Reflection ...................... 110
3.6 Briefing on Numerical Simulation Techniques ........... 117
3.6.1 Basic Equations ................................ 118
3.6.2 General Methods ................................ 119
References ................................................. 121
4 Subcritical Shocks ......................................... 125
4.1 Introduction .......................................... 125
4.2 Observations .......................................... 128
4.3 Theory ................................................ 134
4.3.1 Subcritical Shock Potential .................... 134
4.3.2 Dissipation Length ............................. 135
4.3.3 Subcritical Cold Plasma Shock Model ............ 137
4.3.4 Extension to Warm Plasma ....................... 139
4.3.5 Dissipation in Subcritical Shocks .............. 141
4.4 Conclusions ........................................... 145
References ................................................. 146
5 Quasi-perpendicular Supercritical Shocks ................... 149
5.1 Setting the Frame ..................................... 149
5.1.1 Particle Dynamics .............................. 150
5.1.2 Foot Formation and Acceleration ................ 154
5.1.3 Shock Potential Drop ........................... 157
5.2 Shock Structure ....................................... 158
5.2.1 Observational Evidence ......................... 158
5.2.2 Simulation Studies of Quasi-perpendicular
Shock Structure ................................ 161
5.2.3 Shock Reformation .............................. 169
5.3 Ion Dynamics .......................................... 166
5.3.1 Ion Dynamics in Shock Reformation .............. 177
5.3.2 Ion Instabilities and Ion Waves ................ 180
5.3.3 The Quasi-perpendicular Shock Downstream
Region ......................................... 189
5.4 Electron Dynamics ..................................... 191
5.4.1 Shock Foot Electron Instabilities .............. 192
5.4.2 Modified-Two Stream Instability ................ 195
5.5 The Problem of Stationarity ........................... 204
5.5.1 Theoretical Reasons for Shocks Being "Non-
stationary" .................................... 205
5.5.2 Formation of Ripples ........................... 210
5.6 Summary and Conclusions ............................... 213
5.7 Update-2012 ........................................... 215
References ................................................. 216
6 Quasi-parallel Supercritical Shocks ........................ 221
6.1 Introduction .......................................... 221
6.2 The (Quasi-parallel Shock) Foreshock .................. 224
6.2.1 Ion Foreshock .................................. 226
6.2.2 Low-Frequency Upstream Waves ................... 235
6.2.3 Electron Foreshock ............................. 246
6.3 Quasi-parallel Shock Reformation ...................... 268
6.3.1 Low-Mach Number Quasi-parallel Shocks .......... 269
6.3.2 Turbulent Reformation .......................... 273
6.4 Hot Flow Anomalies .................................... 291
6.4.1 Observations ................................... 291
6.4.2 Models and Simulations ......................... 295
6.4.3 "Solitary Shock" ............................... 302
6.5 The Downstream Region ................................. 303
6.5.1 Sources of Downstream Fluctuations ............. 305
6.5.2 Downstream Fluctuations and Turbulence ......... 314
6.6 Summary and Conclusions ............................... 320
6.7 Update-2012 ........................................... 322
References ................................................. 323
7 Particle Acceleration ...................................... 333
7.1 Introduction .......................................... 333
7.2 Accelerating Ions when They Are Already Fast .......... 337
7.2.1 Diffusive Acceleration ......................... 339
7.2.2 Convective-Diffusion Equation .................. 344
7.2.3 Lee's Self-consistent Quasilinear Shock
Acceleration Model ............................. 349
7.3 Observations .......................................... 359
7.4 The Injection Problem ................................. 362
7.4.1 Ion Shock Surfing .............................. 363
7.4.2 Test Particle Simulations ...................... 364
7.4.3 Self-consistent Shock Acceleration
Simulations .................................... 366
7.5 Accelerating Electrons ................................ 374
7.5.1 Introductory Remarks ........................... 375
7.5.2 The Sonnerup-Wu Mechanism ...................... 376
7.5.3 Hoshino's Electron Shock Surfing Mechanism ..... 378
7.6 Conclusions ........................................... 390
7.7 Update-2012 ........................................... 393
References ................................................. 394
8 Final Remarks .............................................. 399
II Applications: Two Kinds of Collisionless Shocks in the
Heliosphere ................................................ 405
9 Introduction ............................................... 407
10 Planetary Bow Shocks ....................................... 411
10.1 Introduction .......................................... 411
10.2 Terrestrial Type Bow Shocks ........................... 413
10.2.1 Earth's Bow Shock .............................. 414
10.2.2 Mercury's Bow Shock ............................ 421
10.2.3 Jupiter's Bow Shock ............................ 424
10.2.4 Saturn, Uranus, Neptune ........................ 429
10.3 Mars and Moon ......................................... 437
10.3.1 Lunar Mini-Bow Shocks .......................... 437
10.3.2 Mars - A Pile-Up Induced Bow Shock ............. 440
10.4 Venus and the Comets .................................. 443
10.4.1 The Venusian Bow Shock ......................... 444
10.4.2 Cometary Bow Shocks ............................ 449
10.5 Conclusions ........................................... 454
References ................................................. 456
11 The Heliospheric Termination Shock ......................... 463
11.1 The Outer Heliosphere ................................. 463
11.2 Arguments for a Heliospheric Termination Shock ........ 466
11.3 The Global Heliospheric System ........................ 467
11.4 Termination Shock Properties: Predictions ............. 469
11.5 Observations: The Voyager Passages .................... 473
11.5.1 Radio Observations ............................. 474
11.5.2 Plasma Waves and Electron Beams ................ 476
11.5.3 Traces of Plasma and Magnetic Field ............ 480
11.5.4 Energetic Particles ............................ 482
11.6 Conclusions ........................................... 489
11.7 Update-2012 ........................................... 490
References ................................................. 491
Index ......................................................... 495
|
