The relationship of energy flow at the magnetopause to geomagnetic activity

Abstract

Properties of the energetic electron (E ≳ 200 keV) magnetopause layer along the distant magnetotail have been studied with Caltech instrumentation aboard IMP‐8 for approximately 60 spacecraft orbits. The cross‐sectional area of the layer appears to increase by a factor of ∼ 5 with increasing geomagnetic activity, and the average unidirectional electron flux within the layer increases by a factor of ∼ 4. The energy carried by electrons ≳ 200 keV ranges from ∼ 1014 ergs sec−1 to ∼ 1015 ergs sec−1. Extrapolation to include all electrons > 1 keV suggests total energy flow ranging from ∼ 3×1015 ergs sec−1 at quiet times to ∼ 5×1018 ergs sec−1 at magnetically disturbed times.