In the past two decades a succession of direct observations by satellites, and of extensive computer simulations, has led to the realization that the polar ionosphere plays a principal role in large-scale magnetospheric processes - a manifestation of the physics linkage involved in solar-terrestrial. Spatial/temporal variations in high-latitude electromagnetic phenomena, such as dynamic aurorae, electric fields and currents, have proved to be extremely complex. Now the challenge is to comprehend the vast amount of complicated measurements made in this magnetosphere-ionosphere system of the Earth. This book addresses the electrical coupling between the hot, but dilute, magnetospheric plasma and the cold, but dense, plasma in the ionosphere. The significance as well as difficulty in understanding how the basic observed phenomena is thoroughly discussed. In five major chapters, this book presents: basic properties of magnetosphere-ionosphere coupling; morphology of electric fields and currents at high latitudes; global modelling of magnetosphere-ionosphere coupling; modelling of ionospheric electrodynamics; and current issues, such as auroral particle acceleration, substorms, penetration of high-latitude fields into low latitudes.

Table of Contents:
1 Implications of Magnetosphere-Ionosphere Coupling.- 1.1 Solar Wind, Magnetosphere, and Ionosphere.- 1.1.1 Entry of Energy into the Magnetosphere.- 1.1.2 Dissipation of Energy in Substorms.- 1.2 Basic Properties of Magnetosphere-Ionosphere Coupling.- 1.2.1 Global and Local Coupling Processes.- 1.2.2 Plasma Convection.- 1.2.3 Theoretical Approach.- 2 Morphology of Electric Fields and Currents at High Latitudes.- 2.1 Large-Scale Current Systems.- 2.1.1 Convection Electrojets.- 2.1.2 Substorm Current Wedge.- 2.1.3 Polar Cap and Cusp Currents.- 2.1.4 Eastward Current in the Dawn Sector.- 2.1.5 Current Closure in the Magnetosphere.- 2.1.6 Charge Carriers of Field-Aligned Currents.- 2.2 Electric Field and Currents Associated with Auroral Forms.- 2.2.1 Auroral Arcs.- 2.2.2 Westward Traveling Surges.- 2.2.3 Auroral Omega Bands.- 2.2.4 Pulsating Auroral Patches.- 3 Global Modeling of Magnetosphere-Ionosphere Coupling.- 3.1 Basic Concepts.- 3.2 Simulation of Magnetospheric Convection.- 3.2.1 Global Convection Model.- 3.2.2 Plasma Transport Model.- 3.3 Reproduction of Observed Features.- 3.4 Coupling Models with Specific Physical Aspects.- 4 Modeling of Ionospheric Electrodynamics.- 4.1 Ionospheric Parameters Controlled by Field-Aligned Currents.- 4.1.1 Basic Algorithm.- 4.1.2 Quiet Periods.- 4.1.3 Substorm Times.- 4.1.4 Cusp Structure.- 4.2 Magnetogram-Inversion Technique.- 4.2.1 Essence of the Scheme.- 4.2.2 Advantages and Limitations.- 4.2.3 Global Distribution of Ionospheric Parameters.- 4.2.4 Recent Improvements.- 4.3 Formation of Auroral Arcs.- 5 Current Issues in Magnetosphere-Ionosphere Coupling.- 5.1 The Westward Traveling Surge.- 5.1.1 Dynamics.- 5.1.2 Distortion of Convection Pattern.- 5.1.3 Pulsations.- 5.2 Auroral Particle Acceleration and Parallel Electric Fields.- 5.2.1 Observations.- 5.2.2 Theories and Computer Simulations.- 5.3 Penetration of High-Latitude Electric Fields / into Low Latitudes.- 5.3.1 Substorm Effects.- 5.3.2 Source Mechanisms.- 5.3.3 Global Patterns of Ionospheric Fields.- 5.3.4 Shielding of Convection Fields in the Magnetosphere.- 5.4 Relative Importance of Conductivities and Electric Fields..- 5.4.1 Simultaneous Measurements of Ionospheric Parameters.- 5.4.2 Two Electrojet Modes.- 5.4.3 Latitudinal Cross-Sections of the Auroral Electrojets.- 5.4.4 Implications for Substorm Dynamics.- 5.4.5 Future Problems.- References.