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Y. Yung, C. D. Parkinson (Caltech), A.-S. Wong (U. Michigan), A. I. Stewart (U. Colorado)
Jupiter has a large magnetosphere that episodically precipitates large amounts of energy into the polar atmosphere, giving rise to intense auroras. An important consequence of this energy influx is the production of a dark haze (Wong et al., 2003). In our model we explore the sensitivity of the haze production to (a) ion-induced chemistry, (b) temperature, and (c) eddy diffusion coefficient. The chemical production of the haze is initiated by the dissociation of methane by energetic particles, followed by neutral and ion reactions. This eventually leads to the formation of polycyclic aromatic hydrocarbons and other complex hydrocarbons, some of which condense to form the haze. The production is enhanced at higher temperatures and by more effective eddy mixing due to the intense auroral energy input, but the latter is poorly quantified for the polar mesosphere of Jupiter. A search for evidence for enhanced mixing has been carried out using the Cassini observations of the He 584 A during the Jupiter flyby in 2000. New calculations of the Jovian He 584 A airglow intensity, using radiative transfer models with partial frequency redistribution and inhomogeneous atmospheric models, are presented. Our reference conditions assume a helium mixing ratio of 0.136, an appropriate He 584 A solar flux, with a solar line FWHM of 120 mA, and an atmosphere consistent with the Voyager UVS occultation/Cassini polar observation results. We derive the range for the eddy diffusion coefficient at the homopause, Kh, compatible with the Cassini He 584A airglow measurements.
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.