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G.R. Gladstone (SwRI), R. Montez (UT Austin), J.H. Waite, Jr. (U. Michigan), J.T. Clarke (BU)
Long slit echelle spectra that resolve the line profile of Jupiter's auroral Ly\alpha emissions have been obtained by HST-STIS. About 15% of all the UV emissions in Jupiter's aurora are carried by the Ly\alpha line and it provides a useful diagnostic of conditions in the upper atmosphere. The auroral Ly\alpha line profile is self-reversed and has an asymmetry which is most easily explained as due to a Doppler-shifted extinction by a high-speed (i.e., several km/s) stream of H atoms above the aurora. This neutral wind of H atoms could be due to the jovian electrojet, which is seen in near-IR observations of Doppler shifted H3+ emissions. These observations of the Ly\alpha line profile may be used to map the dynamics of Jupiter's upper atmosphere. We present here 1-D and the first 2-D model simulations of the radiative transfer of jovian auroral Ly\alpha emissions, including the effects of the electrojet on the line profile, with application to the HST-STIS data.