Accession Number : AD0688441

Title :   LARGE TEMPORAL VARIATIONS OF ENERGETIC ELECTRON INTENSITIES AT MID-LATITUDES IN THE OUTER RADIATION ZONE.

Descriptive Note : Progress rept.,

Corporate Author : IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY

Personal Author(s) : Yeager,D. M. ; Frank,L. A.

Report Date : FEB 1969

Pagination or Media Count : 42

Abstract : 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)

Descriptors :   (*VAN ALLEN RADIATION BELT, ELECTRON DENSITY), PERIODIC VARIATIONS, CHARGED PARTICLES, MAGNETIC STORMS, SPACE ENVIRONMENTS

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE