Radiation Belts of Jupiter: A Second Look

Abstract

The outbound leg of the Pioneer 11 Jupiter flyby explored a region farther from the equator than that traversed by Pioneer 10, and the new data require modification or augmentation of the magnetodisk model based on the Pioneer 10 flyby. The inner moons of Jupiter are sinks of energetic particles and sometimes sources. A large spike of particles was found near lo. Multiple peaks occurred in the particle fluxes near closest approach to the planet; this structure may be accounted for by a complex magnetic field configuration. The decrease in proton flux observed near minimum altitude on the Pioneer 10 flyby appears attributable to particle absorption by Amalthea.

The size distribution of Jupiter's main ring from Galileo imaging and spectroscopy

“…The first evidence that Jupiter possesses a ring system came from the Pioneer 10 and 11 particle flux measurements (Fillius et al, 1975;Acuña and Ness, 1976). However, the existence of a ring system around Jupiter was not proven until Voyager 1's Imaging Science Subsystem (ISS) returned a smeared, multiply exposed image of the main ring in March 1979.…”

Keck observations of the 2002–2003 jovian ring plane crossing

“…Hints of the existence of Jupiter's ring system were first obtained in 1974, when Pioneer 11 detected "drop-outs" in the measurements of charged particle data (van Allen et al 1975;Fillius et al 1975). The nature of the system became much clearer in 1979, when Voyagers 1 and 2 obtained the first images of Jupiter's rings (Smith et al 1979a(Smith et al , 1979b.…”

“…Hence, to effectively stop 10-20 MeV electrons takes pebbles or rocks larger than several cm. These particles make up the parent bodies in the ring, and are the same bodies responsible for the observed drop-out in the in situ measurements of charged particles by Pioneer 11 (Van Allen et al 1975;Fillius et al 1975). Typically, 10-20 MeV electrons traverse the main ring with a width of ∼ 1000 km in about 6 days (de Pater, 1981).…”

Jupiter's radiation belts

“…Taken togethe r , the various packages provided coverage f r o m -120 keV to > 80 MeV. Detailed results specifically pertaining to protons in the radiation belt s of Jupiter are given by Fillius (1976), Fillius and Mdflwain ( l974a ,b), Fillius et al (1975), McDonald and Trainor (1976), Simpson (1974, 1975) , Simpson and McKibben (1976) , Simpson et al ( 1974a , b;1975a , b ) , Train or et al ( 1974a , b; , Van Allen ) , and Van Allen et al ( 1974b. Some representative findings a r e recounted here.…”