Multi-satellite characterization of the large energetic electron flux increase at L = 4-7, in the five-day period following the March 24, 1991, solar energetic particle event

Following the giant magnetic storm that started on March 24, 1991, and the immediately-preceding solar energetic particle (SEP) event, a dramatic increase in the flux of energetic electrons was observed to occur on several satellites (using Los Alamos instruments aboard two geosynchronous satellites and two GPS satellites, plus energetic electron data from the CRRES satellite) sampling the L=4-7 region of the magnetosphere. We find that: this flux buildup at the larger L-values (L--6-7) first appears near the magnetic equator and subsequently spreads to higher magnetic latitudes; the flux buildup near the magnetic equator peaks first at the higher L before it peaks at the lower L; analysis of the angular distribution of energetic electrons at geosynchronous orbit shows that the flux buildup begins first with the buildup of energetic electrons (>300 keV) moving perpendicular to the magnetic field.