A two-dimensional model of plasma transport and chemistry in the Jovian magnetosphere

A two-dimensional model of plasma transport and chemistry in the Jovian inner magnetosphere that enables us to calculate ion and electron densities and temperatures as well as their radiative emission properties is presented. As input data, the model uses (assumed) neutral densities, arbitrary initial ion densities, and ion and electron (both thermal and hot) temperatures given by the published empirical model derived from Voyager data. Six thermal ion species, three hot ion species, and both thermal and hot electrons are included. The calculated ion partitioning is similar to the results of previous numerical models (rather than the empirical model). The observed general increase in temperature of both the ions and electrons versus distance can be accounted for by a distributed neutral source. Model electron temperature (and thus torus emission) was found to be less than expected. Of three proposed mechanisms that might account for the observed electron heating, namely, (1) an increase in the temperature of the thermal ions, resulting in electron heating via Coulomb collisions, (2) hot ions, presumably of ring current origin, diffusing inward and heating the thermal electrons, and (3) a flux of suprathermal electrons, alternative (2) is most strongly supported by our model.