Observations of Jovian upstream events by Ulysses

Abstract

The heliosphere instrument for spectra composition and anisotropy at low energy (HISCALE) experiment on board the Ulysses spacecraft, during the Jovian flyby, measured 192 distinct 61-77 keV upstream ion events of probable Jovian origin. Event-averaged characteristics such as intensities, anisotropies, power law spectral exponents, averaged event duration, and magnetic field configurations were obtained. Within 1000R_J, all ion observations >2.92 particles/(cm²srskeV) were found to be of probable Jovian origin. Evidence for velocity dispersion and convecting spatial structures was discovered through detailed analysis of individual events. Jupiter was found to be a significant source of interplanetary ions and electrons.