LARGE TEMPORAL VARIATIONS OF ENERGETIC ELECTRON INTENSITIES AT MID-LATITUDES IN THE OUTER RADIATION ZONE.
IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY
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A thorough search of Explorers 12 and 14 observations of electron 40 keV E 2 MeV intensities within the outer radiation zone during the period 1961-1963 has provided evidences of several catastrophic rapid decreases and recoveries of these electron intensities within periods of approximately several minutes at L-values of approximately 5 to 6. Typical values for these intensity fluctuations are by factors 500, 100 and 1000 for electrons E 40 keV, 230 keV and 1.6 MeV, respectively. A comparison of the temporal variations of integral energy spectrums of electron intensities, latitudes of the observed events, ground-based observations of auroral magnetic activity, and low-altitude measurements of electron intensities within the above energy range allow this striking phenomenon to be interpreted in terms of redistribution of these outer zone electrons during the distortion of the geomagnetic field by the low-energy plasma producing the associated magnetic disturbance and of conservation of the first two adiabatic invariants Mu and I. The principal features of these events are adequately accounted for with the above interpretation, as the signature of the motion of the trapping boundary for energetic electrons at mid-latitudes in the dark hemisphere of the magnetosphere, which eliminates the alternative assumption of an almost unreasonably strong acceleration mechanism for outer zone energetic electrons. Author
- Atmospheric Physics