On the basis of comparison of radio data and model calculations of Jupiter's synchrotron radiaton the 'hot region' or east--west asymmetry in the planet's radiation belts is proposed to be due to the combined effect of an overabundance of electrons at jovicentric longitudes &lgr;J~240 ¿--360 ¿ and the existence of a dusk dawn directed electric field over the inner magnetosphere, generated by the wind system in the upper atmosphere. The model calculations were based upon the magnetic field configurations derived from the Pioneer data by Acuna and Ness [1976> (the O4 model) and Davis, Jones and Smith (quoted in Smith and Gulkis [1979>) (the P11 (3,2)A model), with an electron distribution derived in the first paper of this series [de Pater, this issue>. We would infer from the calculations that the O4 model gives a slightly better fit to the data; the relatively large number density at &lgr;J~240 ¿--360 ¿, however, might indicate the presence of even higher order moments in the field.