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Takehiko Satoh (FRCCS/SUT), J. E. P. Connerney (NASA/GSFC)
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The distribution of H3+ emissions in Jupiter{'}s polar region is interpreted in terms of the corresponding magnetospheric sources, by reference to corrected Jovimagnetic coordinates based on the VIP4 magnetic field model of Connerney et al. (1998). Two sets of 3.43-\micron\ auroral images acquired with NSFCAM at NASA IRTF during the summer of 1996 were analyzed utilizing a generalized inverse methodology (Satoh et al. 1996) applied to pixel-by-pixel comparison of the observed and the model intensities. In our emission source model, four representative ovals, traced from the Jovigraphic equator at 6 R\rm j (Jovian radii), 8 R\rm j, 12 R\rm j, and 30 R\rm j radial distances are used to divide the polar region into zones. The model also includes a longitude-dependent intensity variation in each zone bounded by two adjacent ovals, intensity variation with local time, and altitude above the methane homopause.
The most intense (main oval) emissions are found between the 12 R\rm j and 30 R\rm j ovals. The peak brightness occurs at System-III longitude \lambda\rm III ~ 260\circ in the north, and ~130\circ in the south, in association with the minimum surface magnetic field magnitudes of the VIP4 model. Between the 8 R\rm j and 12 R\rm j ovals, the peak brightness occurs at \lambda\rm III ~ 215\circ in the north, and at ~ 25\circ in the south, consistent with Satoh et al.'s (1996) System-III anomalies. These intensity peaks may originate from the ``windshield wiper'' effects of drifting electrons, caused by pitch angle scattering of varying efficiency from the inner to distant magnetosphere. The total H3+ emission flux is estimated as 2-4 \times 1012 W in each hemisphere. The power output by H3+ emission from the auroral atmosphere is comparable to the power input, in the form of precipitating 10-keV electrons, required by Achilleos et al.'s (1998) Jovian ionospheric model.
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The author(s) of this abstract have provided an email address for comments about the abstract: tsatoh@rs.noda.sut.ac.jp