Three-Dimensional Modelling of EUVE Observations of the Io Plasma Torus

Abstract

First results from a 3-D model of EUVE observations of the Io Plasma Torus are reported. The semi-empirical model calculations follow a method previously used to describe visible and near-UV emissions. The extension to EUV wavelengths is described. Several EUV emissions have been successfully modelled although some discrepancies remain at this stage. Most EUV emissions peak at a jovicentric distance of ≈ 5.8 RJ. The observed dawn-dusk asymmetry of the torus was well fitted with a shift parameter (ϵ) of 0.03. The modelling also indicates that optical depth effects need to be considered for several EUV emission lines.