How the Earth's inner magnetosphere works: An evolving picture

This tutorial review deals with large-scale convection electric fields in Earth's inner magnetosphere and the particle populations that interact strongly with those fields, specifically the inner plasma sheet, ring current, and plasmasphere. We summarize the state of knowledge in the early 1970s, by which time most of the major observational features had been discovered and much of the basic theory had been developed. The review then focuses on how observational knowledge and theoretical understanding have increased since the early 1970s in several areas, specifically prompt-penetration electric fields; polarization jets (PJs), subauroral ionization drifts (SAIDs), and subauroral polarization streams (SAPS); ring current dynamics; and large-scale plasmasphere dynamics.