Thermal plasma in the inner kronian magnetosphere

Since the flybys of the twin Voyager spacecraft through the magnetosphere of Saturn in the early 1980s, conflicting interpretations of the phenomena observed have appeared in the literature. An attempt is made here to constrain the transport rate in the inner magnetosphere by appeal to plasma observations of density and temperature. The conflicting models range from those entailing fast transport, which limits the density, to models in which the ion density is limited by the process of recombination. The coupled differential equations for Coulomb and radiative heat transfer between hot electrons, thermal electrons and thermal heavy ions are solved. It is concluded that diffusive transport is not the dominant factor in determining the plasma state of the inner magnetosphere of Saturn. Support is found for a previously proposed model of a ring source for the cold dense plasma observed by Voyager 2 at the ring plane crossing.