A model of energy deposition of energetic electrons and EUV emission in the Jovian and Saturnian atmospheres and implications

A model of the interaction between incident electron precipitation and H2 atmospheres is described. The local degraded primary and secondary electron energy distributions are calculated by using the continuous slowing down approximation. The altitude distribution of the ionization rate and various H and EUV H2 emissions are calculated for four different incident electron spectra. A total EUV H2 emission efficiency of 10.6 kR/incident erg/sq cm per sec is obtained for a pure H2 atmosphere. Comparison with the Voyager Jupiter observations indicates that an incident energy flux of about 8 ergs/sq cm per sec was present at the time of the encounter if the emission is located in an H2-dominated region. The local thermospheric heating rate was about 4 ergs/sq cm per sec for Jupiter and of the order of 0.1 erg/sq cm per sec for Saturn. A globally averaged atomic hydrogen production rate of about 1 x 10 to the 10th atoms/sq cm per sec is induced by the Jovian auroral electron precipitation, largely exceeding the solar EUV dissociation rate.