The Galileo Energetic Particles Detector is fully described byWilliams et al [WILLIAMSETAL1992].
Jupiter possesses the largest planetary magnetosphere in thesolar system. It is the largest in spatial dimension, has the highesttrapped particle energies and intensities, has the greatestcompositional variety in its major particle populations, displays thelargest co-rotational effects and has the largest number of moonswithin the magnetosphere that provide both strong sources for andlosses of the observed particle populations. These characteristics,uncovered by the Pioneer and Voyager flybys demand an instrumentdesign capable of accommodating the great range in parametric valuesestablished by these extremes.
Within the Jovian magnetosphere, the energetic (>=20 keV)particle populations play an important dual role. First, theyrepresent a major factor in determining the size, shape, and dynamicsof the system. For example, observations of energetic particleintensities and corresponding energy densities show that thesepopulations are important in (1) standing off the solar wind andthereby determining magnetopause position; (2) determining the generalmagnetic field configuration in the evening magnetosphere and (3)establishing the bulk of the ring current responsible for themagnetodisk configuration of the middle-Jovian magnetosphere.