Direct detection of asymmetric increases of extraterrestrial ‘ring current’ Proton intensities in the outer radiation zone

Abstract

Measurements of the spatial distributions and temporal variations of the extraterrestrial ‘ring current’ proton intensities near the magnetic equator during selected phases of two moderate magnetic storms on July 9 and September 8, 1966, provide direct evidence of asymmetric enhancement of these proton intensities deep in the outer radiation zone, during the early development of the latter magnetic storm. Increases of these low-energy proton (5 ≲E≲50 kev) intensities in the evening-midnight quadrant of the outer radiation zone on L shells ≃3.5 to 5.0 were accompanied by a substantial polar magnetic substorm observed during similar local times. However, no increases of proton intensities at levels above those typical of the ‘quiescent ring current’ centered at L∼6.5, were yet observed near local noon, several hours later. Several implications that concern the origin and motions of this plasma during the early development phase of the magnetic storm are discussed.