P. F. Mizera

Auroral plasmas in the evening sector - Satellite observations and theoretical interpretations

Observations and theoretical interpretations of auroral plasma distributions have led to a spectacular advance, in the latter part of the 1970s, in understanding the formation of auroral arcs and the role that the aurora plays in the coupling between the magnetosphere and ionosphere in the evening sector. The key to this understanding is the verification of the existence of electric field components parallel to the magnetic field. The parallel electric field accelerates electrons downwards to form the aurora. At the same time, it accelerates ionospheric ions upwards to provide the magnetosphere with a new source of hot plasma. The auroral plasma observations indicate that the hot auroral plasmas behave according to laws of adiabatic motion coexisting with a measure of plasma turbulence. Theoretical considerations of auroral arc formation are in accord with this plasma characteristic.