37th DPS Meeting, 4-9 September 2005
Session 30 Outer Planets
Poster, Tuesday, September 6, 2005, 6:00-7:15pm, Music Lecture Room 5

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[30.11] Jupiter's ionosphere with improved sources of H2(v) molecules

T. Majeed (American University of Sharjah, UAE/University of Michigan, USA), R. V. Yelle (U. Arizona), J. H. Waite (U. Michigan)

We have used an improved radiative transfer model for the solar-induced resonance fluorescence source of H2 vibrational quanta for differing solar zenith angles to study the distribution of excited vibrational levels of ground electronic state of H2 (H2(v)) and their impact on ionospheric electron densities in the upper thermosphere of Jupiter. An improved photoelectron source of H2(v) is also included with numerous modifications to our electron transport model. These sources appear to be more important for the production of vibrationally excited H2 (v>3) compared with other sources, such as direct vibrational excitation by electron impact and dissociative recombination of H3+ ions. Combining the strength of these sources in our ionosphere-thermosphere model, we calculate the density distribution for each of the 14 vibrationally excited levels self-consistently with ionospheric electron and ion densities as a function of local time. While interpreting the Galileo RSS electron density profiles at local dusk, we find that the chemical sink for the main ionospheric ion, H+, has increased as a result of sufficiently abundant densities of H2 (v>3) molecules. This results in reduced ionospheric electron densities, but not reduced enough to explain the characteristics of the measured ionospheric peak density of the Jovian ionosphere. We also show that a vertical plasma drift induced by horizontal neutral winds or a dynamo electric field is required to account for the peak altitude in the measured electron density profiles.

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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.