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T. Satoh (Kumamoto University), J. E. P. Connerney (NASA GSFC)
Precisely how Jupiter's aurorae respond to magnetospheric dynamics is not well understood. Recent theoretical models predict less intense aurorae in response to increased solar wind ram pressure (Southwood and Kivelson, 2001; Cowley and Bunce, 2001) but this is at odds with what is observed in the infrared (Baron et al., 1996).
The IR observations are better suited to the study of dynamics, compared to UV observations. IR emissions are thermally excited H3+ lines, with a response time (few hundred seconds) much longer than that of UV aurorae. The H3+ aurora is a good measure of time-averaged precipitation flux to the ionosphere, and well matched to the estimated magnetospheric response time of a few hours (Cowley and Bunce, 2001).
Jupiter's aurora consists of several individual components which originate from different source regions in the magnetosphere (Satoh and Connerney, 1999). We extend the analysis of Baron et al. (1996) using high resolution NSFCAM (IRTF) images obtained on 14 nights in 1999. The higher spatial resolution of the NSFCAM imagery allows us to pinpoint the relative brightness variations among the several distinct auroral components. This can provide important clues regarding how Jupiter's magnetosphere responds to the solar wind. We analyze the night-to-night variations in auroral brightness, changes in visibility of the main oval, and discuss comparison with the solar wind dynamical pressure.
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Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.