Abstract
After 1958, when scientific satellites began exploring the Earth magnetic environment, many puzzling phenomena could be directly examined, especially the polar aurora and disturbances of the Earth's magnetic field [see Stern, 1989a]. The notion of the solar wind, introduced that same year, helped clarify the role of the Sun in driving such phenomena. The large-scale structure of the magnetosphere, the space region dominated by the Earth's magnetic field, was gradually revealed within the next decade: its trapped particles, its boundary, and its long magnetic tail on the night side. Inevitably, however, the new discoveries led to new questions at a more fundamental level, about the transfer of energy, the flow patterns of plasmas and electric currents, the acceleration of the aurora, and about transient events such as magnetic substorms and storms, which energized ions and electrons. Though significant progress has occured in some of these areas, many unresolved issues still remain. This review outlines the history of magnetospheric research, draws some general conclusions and provides an extensive bibliography.

Clicking on any marked section on the list below brings up a file containing it and all unmarked sections immediately following it on the list. This list is repeated at the beginning of each file.

1. Introduction
2. Discovery of the Radiation Belts
3. Artificial Belts and Early Studies
4. The Large Scale Structure
5. Convection
6. Reconnection
7. The Open Magnetosphere
8. Observational Tests
9. The Polar Aurora
10. Field Aligned Voltage Drops
11. Birkeland Currents
12. Substorms: Early Observations
13. Substorms: The Satellite Era
14. Substorms: Theory
15. Convection in the Geotail
16. Planetary Magnetospheres
17. Other Areas
18. Assessment

1. Introduction

This is the second part of a concise history of observations of the Earth's magnetosphere and of their interpretation. It and the first part [Stern, 1989a, henceforth denoted BH-1] are meant to help trace the development of magnetospheric physics in a unified context and to outline its framework of observations and ideas. The early years, around 1957-64, are covered chronologically, after which the coverage is arranged by topics--convection, reconnection, aurora, Birkeland currents and substorms. At the end some overall trends are assessed, as well as the current state of the discipline. Readers who find this article too technical are referred to an exposition on the world-wide web by Stern and Peredo [1995].

This brief account is based primarily on work published in English, which covers US efforts fairly completely but is unfortunately far less detailed on space research in the USSR and elsewhere. The first part (BH-1) covered earthbound studies of the magnetosphere before artificial satellites were available, and here the rest of the story is presented. The concluding section contains an assessment of overall trends as well as of the current state of the discipline.

This account is mainly based on published source, rather than on personal papers or interviews. It must therefore be viewed as a mere framework, in which many details remain to be filled.

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• David P. Stern - NASA/GSFC Code 695 (u5dps@lepvax.gsfc.nasa.gov)
• Mauricio Peredo - Hughes STX Corporation (peredo@istp1.gsfc.nasa.gov)

Last updated March 13, 1999