H Lyman α line in Jovian aurorae: electron transport and radiative transfer coupled modelling

Laboratoire de Planétologie de Grenoble, BP 53, 38041 Grenoble Cedex 1, France e-mail: helene.menager@obs.ujf-grenoble.fr

Received: 27 July 2009
Accepted: 10 November 2009

Abstract

Aims. The aim of this work is to characterize the impact of the solar UV flux and of the electron precipitation on Jupiter's atmosphere and to study the H Lyman α intensity and spectral profile in Jupiter's aurorae. In particular we characterize the sensitivity of the line to the relevant input parameters.

Methods. We use a multi-stream electron transport code solving the 1D Boltzmann equation and a Feautrier technique radiative transfer code.

Results. We calculate ionization rate profiles of the main species of Jupiter's ionosphere and the heating rate due to electron precipitation, as a function of the energy of the precipitation. We also calculate the emission rate of Lyman α photons under auroral electron precipitation and the ensuing line profile. The profile exhibits a centre reversal which could be used as a diagnostic of Jupiter's auroral low-energy electron precipitation.