DPS 2001 meeting, November 2001
Session 33. Outer Planet Magnetospheres
Oral, Chair: R. Gladstone, Thursday, November 29, 2001, 3:30-4:20pm, Regency GH

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[33.04] HST Images of Jupiter's UV Aurora: Mirrors of a Strongly Corotational Magnetosphere

G.E. Ballester (LPL, U. Arizona), R.J. Walker, M.G. Kivelson, K. Khurana (UCLA), F. Herbert (LPL, U. Arizona)

Over the past decade, the Hubble Space Telescope has acquired an impressive imaging dataset of Jupiter's UV auroral emissions, signatures of the particle and energy deposition onto the upper atmosphere and ionosphere from interaction processes with the magnetosphere, and thus, mirrors of the global state and configuration of the magnetosphere resulting from the most recent interaction with the impinging solar wind. We will present some features of the aurora, both repetitive and relatively rare, that we are identifying primarily from the WFPC2 observations since they imaged the north and south polar aurorae simultaneously with adequate sensitivity. For example, we will show clear and simple evidence of the dependence of the auroral emissions on the local time of the associated magnetospheric regions driving the particle precipitation, regions that are therefore strongly influenced by the solar wind interaction. This evidence is derived from the pronounced afternoon brightening observed in the south aurora throughout a full Jovian rotation, and also from a small number of images that do not show this behavior. From the latter we can isolate the corresponding magnetospheric local time signature in the north aurora. We will also present some results derived from intercomparison of the HST auroral images taken simultaneously with in-situ measurements made by the Galileo orbiter in 1996, and with related MHD modeling of the magnetosphere and solar wind interaction. These will include a set of images spanning several days (not continuously) that show interesting behavior both globally and in the dawn regions where Galileo also sampled interesting magnetic field variations. We will show MHD modeling results, such as of a small polar cap (attached to open field lines bent tailwards) on the north hemisphere as expected from auroral images. We will further explore possible effects of the strong corotational forcing in driving energetic field aligned currents that produce aurora in different magnetospheric regions.

The author(s) of this abstract have provided an email address for comments about the abstract: gilda@vega.lpl.arizona.edu

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