Contents -- 1. Introduction -- 1.1 Geomagnetism -- 1.2 The Discovery of the Solar Wind and the Magnetosphere -- 1.3 Viscous Convection -- 1.4 Reconnection-Driven Convection -- 1.5 Petschek Reconnection -- 1.6 Substorms -- 1.7 Overview -- 1.8 The Equilibrium Magnetosphere -- 1.9 The Convecting Magnetosphere -- 1.10 Auroral and Magnetospheric Substorms -- 2. The Teardrop Magnetosphere -- 2.1 Introductory Remarks -- 2.2 The Teardrop Model -- 2.3 The Position and Shape of t he Magnetopause -- 2.4 The Thickness of the Magnetopause Current Layer -- 2.5 The Position and Shape of the Bow Shock -- 2.6 The Failure of Weak-Field MHD and the "Plasma Depletion Layer" -- 2.7 Standing Slow and Intermediate Waves in the Magnetosheath -- 2.8 Summary -- 3. The Bell-Like Magnetosphere -- 3.1 Introductory Remarks -- 3.2 Geomagnetic Pulsations -- 3.3 Coupling of Magnetopause Motions to Resonant Alfven Waves -- 3.4 The Eigenmodes of the Magnetospheric Cavity -- 3.5 Observations of Standing Alfven Waves -- 3.6 Occurrence and Distribution of Slanding-Wave Harmonics -- 3.7 Observations of the Global Mode -- 3.8 Response of the Magnetosphere to Passing Solar Wind Structure -- 3.9 The Response of the Magnetosphere to Interplanetary Shocks -- 3.10 Magnetospheric Response to Solar Wind Tangential Discontinuities -- 3.11 Ionospheric Response to Sudden Pressure Variations in the Solar Wind -- 3.12 Quasiresonant Response to Solar Wind Pressure Pulses -- 3.13 Summary -- 4. The Viscous Magnetosphere -- 4.1 Introductory Remarks -- 4.2 The Low-Latitude Boundary Layer -- 4.3 Field-Aligned Currents -- 4.4 The Ionospheric Footprint of the Low-Latitude Boundary Layer -- 4.5 Micropulsations Associated with the Kelvin-Helmholtz Instability -- 4.6 Vortex Auroras -- 4.7 Vortex Structures in the Plasma Sheet -- 4.8 The Boundary Layer in the Magnetospheric Tail.

4.9 Boundary Layer Transport -- 4.10 Summary -- 5. The Reconnecting Magnetosphere -- 5.1 Introductory Remarks -- 5.2 The Polar Rain -- 5.3 The Polar Wind -- 5.4 The Auroral Oval -- 5.5 The Plasmasphere -- 5.6 Direct Evidence for Dayside Magnetopause Reconnection -- 5.7 Precipitation of Magnetosheath Plasma into the Dayside Ionosphere -- 5.8 Direct Entry of Solar Wind Plasma into the Magnetotail -- 5.9 Convection across the Tail Lobes -- 5.10 Average Tail Reconnection Region -- 5.11 Stratification of the Plasma Sheet Boundary Layer -- 5.12 The Length of the Earth's Magnetic Tail -- 5.13 Interaction of the Two Convection Systems in the Ionosphere -- 5.14 Comparison of Viscosity- and Reconnection-Driven Transport -- 5.15 Discussion -- 6. Correlation of Geomagnetic Activity with the Solar Wind -- 6.1 Introductory Remarks -- 6.2 Correlation of Geomagnetic Activity with the Interplanetary Magnetic Field -- 6.3 Dependence of the Convection Rate upon the Interplanetary Field -- 6.4 Dependence of the Polar Cap Convection Pattern upon the Interplanetary Field -- 6.5 Dependence of Field-Aligned Currents upon the Interplanetary Field -- 6.6 Time-Dependent Response to the Changing Interplanetary Field -- 6.7 The Viscous Component of Geomagnetic Activity -- 6.8 Summary -- 7. The Reconnection Substorm -- 7.1 Introductory Remarks -- 7.2 Changes in Magnetopause Position during Substorm Growth Phase -- 7.3 Changes in the Geomagnetic Tail during Substorm Growth Phase -- 7.4 Development of Ionospheric Convection during Growth Phase -- 7.5 Development of Dayside Magnetospheric Convection During Growth Phase -- 7.6 Stimulation of Convection in the Tail Lobes -- 7.7 The "Nearer-Earth Neutral Line" Scenario -- 7.8 Observational Basis of the Nearer-Earth Neutral Line Model . -- 7.9 Plasmoids -- 7.10 Traveling Compression Regions -- 7.11 Plasmoid and TCR Timing.

7.12 Discussion -- 8. Bursty Magnetopause Reconnection -- 8.1 Introductory Remarks -- 8.2 Bursts of Energetic Electronsand Ions near the Magnetopause -- 8.3 Flux Transfer Events -- 8.4 Locations of Reconnection Events Generating FTEs -- 8.5 The FTE Contribution to the Overall Convection Potential -- 8.6 Ionospheric Signatures of Impulsive Magnetopause Reconnection -- 8.7 Cusp-Region ULF Waves -- 8.8 Alfven Waves at the Equatorward Boundary of the Active Cusp -- 8.9 Ion Energy-Latitude Dispersion on Polar Cusp Field Lines -- 8.10 Bursty Ionospheric Flow Events -- 8.11 Transient Dayside Aurora -- 8.12 F-Region Density Patches -- 8.13 Summary -- 9. Bimodal Plasma Sheet Flow -- 9.1 Introductory Remarks -- 9.2 The Plasma Sheet Pressure Paradox -- 9.3 Statistical Properties of Plasma Sheet Transport -- 9.4 Bursts of Plasma Sheet Flow during Steady Solar Wind Conditions -- 9.5 Bursty Bulk Flow Events -- 9.6 Bimodal Plasma Sheet How -- 9.7 High-Speed Flows at Quiet Times -- 9.8 High-Speed Flows and Flux Ropes -- 9.9 High-Speed Flows, Plasmoids, Flux Ropes, and TCRs in the Distant Tail -- 9.10 Dependence of BBF/Plasmoid Properties upon Distance Downfall -- 9.11 Energetic Particle Bursts in the Midtail -- 9.12 Ion Bursts, High-Speed Flows, Boundary Layer Activations, and Bursty Reconnection -- 9.13 East-West Localization of BBF/Plasmoid/Particle Burst Generation Region -- 9.14 Tail Lobe Filaments -- 9.15 Flow Bursts in the Nightside Auroral Ionosphere -- 9.16 The Ionospheric Footprints of B ursty B ulk Flow Events -- 9.17 Comparison of FTE and BBF Flux Transfers -- 9.18 Synthesis -- 10. Convection for Northward Interplanetary Field -- 10.1 Introductory Remarks -- 10.2 Response of Pre-Existing Polar Cap Convection to Northward Field Shifts -- 10.3 Reconnection of Interplanetary and Tail-Lobe Field Lines.

10.4 Signatures of Tail-Lobe Reconnection in Polar Orbit -- 10.5. Reverse Convection in the Polar Cap -- 10.6 Field- Aligned Currents -- 10.7 Seasonal and Day-Night Asymmetries of Polar Cap Convection -- 10.8 Global View of Polar Cap Aurora -- 10.9 Ground-Based View of Sun-Aligned Aurora -- 10.10 Evidence that Some Transpolar Arcs Are on Closed Field Lines -- 10.11 Relation between Sun-Aligned Arcs and Convection -- 10.12 Shrinkage of Tail Lobes in Northward Field Conditions -- 10.13 Evolution of Polar Cap Aurora during a Prolonged Northward Field Interval -- 10. 14 Polar Cap Convection in Conditions of the Most Extreme Geomagnetic Quiet -- 10.15 Discussion -- 11. The Nightside Auroral Oval -- 11.1 Introductory Remarks -- 11.2 Magnetic Field Mapping -- 11.3 Dependence of the Auroral "Oval" upon Geomagnetic Activity -- 11.4 Inherent Uncertainty in Mapping the Poleward Aurora -- 11.5 The Diffuse Aurora -- 11.6 Inverted Vs -- 11.7 Auroral Arcs -- 11.8 Diffuse and Discrete Aurora and their Relationship to Field- Aligned Currents -- 11.9 Arc Occurrence and the Interplanetary Field -- 11.10 The Harang Discontinuity -- 11.11 The Relationship between Arcs and Ionospheric Convection -- 11.12 The Relationship between Arcs and Inverted Vs -- 11.13 Ground Observations of Arcs at the Poleward B order of the Auroral Oval -- 11.14 The Poleward Border of the Oval and the Plasma Sheet Boundary Layer -- 11.15 Auroral Kilometric Radiation and the Poleward Aurora -- 11.16 Physical Mapping of the Nightside Oval into the Plasma Sheet -- 11.17 Conjugacy -- 11.18 Concluding Remark -- 12. The Auroral Substorm -- 12.1 Introductory Remarks -- 12.2 Growth Phase in the Polar Cap -- 12.3 Growth Phase around the Auroral Oval -- 12.4 Classical Evening Sector Growth Phase -- 12.5 Pseudoexpansions -- 12.6 Precursors to Onset -- 12.7 Onset.

12.8 Relation of Onset Arc to Other Auroral Oval Structures -- 12.9 The Westward Surge -- 12.10 The Expanding Auroral Bulge -- 12.11 Fine Structure of the Substorm Expansion -- 12.12 Proton Aurora Substorm -- 12.13 The Phases of the Auroral Substorm -- 12.14 The Relationship between the Auroral Bulge and the Poleward Aurora -- 12.15 Activity in the Poleward Arc System -- 12.16 Equatorward Auroral Activity during the Recovery Phase -- 12.17 The End of the Recovery Phase -- 12.18 Synthesis -- 13. The Geosynchronous Substorm -- 13.1 Development of a Tail-Like Field during the Growth Phase -- 13.2 How Thin Does the Current Sheet Get? -- 13.3 Dipolarization -- 13.4 Dispersionless Injections -- 13.5 The Substorm Current Wedge -- 13.6 Pi 1 and Pi 2 Pulsations and the Timing and Location of Substorm Onset -- 13.7 Generation of Midlatitude Pi 2 -- 13.8 Azimuthal Propagation of Dipolarization near Geostationary Orbit -- 13.9 Size of Initial Dipolarization Region -- 13.10 Radial Propagation of Dipolarization -- 13.11 Plasmoids Escaping from the Geostationary Region -- 13.12 Plasma Sheet Dropouts in the Post-Geosynchronous Region -- 13.13 Plasma Sheet Recoveries in the Postgeosynchronous Region -- 13.14 Summary -- 14. Coordination of the Geosynchronous and Auroral Substorms -- 14.1 Introductory Remarks -- 14.2 The Auroral Expansion and Dipolarization -- 14.3 The Westward Surge and Dipolarization -- 14.4 Multiple Surge Intensification and Oscillatory Dipolarization -- 14.5 Dipolarization and Poleward Arc Brightening -- 14.6 Dependence of Plasma Composition on Solar and Geomagnetic Activity -- 14.7 Dependence of Plasma Sheet Composition on Auroral Activity -- 14.8 Injection of O+ into the Plasma Sheet during Substorm Expansion Phase -- 14.9 Variation of O+ in the Geosynchronous Region During Substorms -- 14.10 Discussion -- 15. Triggered Substorms.

15.1 Introductory Remarks.