HIGH-ENERGY CHARGED-PARTICLES IN THE INNERMOST JOVIAN MAGNETOSPHERE

The energetic particles investigation carried by the Galileo probe mea sured the energy and angular distributions of the high-energy particle s from near the orbit of lo to probe entry into the jovian atmosphere. Jupiter's inner radiation region had extremely large fluxes of energe tic electrons and protons; intensities peaked at similar to 2.2R(J) (w here R(J) is the radius of Jupiter). Absorption of the measured partic les was found near the outer edge of the bright dust ring. The instrum ent measured intense fluxes of high-energy helium ions (similar to 62 megaelectron volts per nucleon) that peaked at similar to 1.5R(J) insi de the bright dust ring. The abundances of all particle species decrea sed sharply at similar to 1.35R(J); this decrease defines the innermos t edge of the equatorial jovian radiation.