Why Does the Aurora Flare up ?

Abstract:

The year 1964 was an interesting year, which has shaped two distinct streams of auroral research in magnetospheric physics. The first approach emphasizes the importance of magnetic reconnection in the magnetotail and has become the main stream. In the second approach, substorms are studied explicitly in terms of the power supply (dynamo), currents/circuits and dissipation (substorms). It is shown that as Alfven emphasized in as early as 1967, the second approach gives a much better understanding of substorms than the first one based on moving magnetic field lines. It is suggested also that the expansion phase onset occurs within 10 Re by other than magnetic reconnection. Substorm research provides many hints in dealing with rarefied plasmas, which are applicable in the solar corona and nebula.