Jupiter's H+3 Emissions Viewed in Corrected Jovimagnetic Coordinates

Abstract The distribution of H + 3 emissions in Jupiter's polar region is interpreted in terms of the corresponding source regions and the energetic in the magnetosphere by reference to corrected jovimagnetic coordinates based on the VIP4 magnetic field model of J. E. P. Connerney et al. (1998, J. Geophys. Res. 103, 11929–11939). Two sets of 3.43-μm auroral images, acquired on May 31/June 1, 1996, and on July 8/July 9, 1996, using NSFCAM at NASA IRTF, were analyzed. Model images were generated for observed rotation phases, and the generalized inverse methodology of T. Satoh et al. (1996, Icarus 122, 1–23) is applied to pixel-by-pixel comparison of intensities to constrain the parameters of the emission source model. The most intense emissions are found between the 12- R j (jovian radii) and 30- R j ovals, representing the main auroral emissions. The System-III longitudes (λ III ) of peak brightness in this zone, λ III ∼ 260° in the north and ∼130° in the south, coincide well with those of the minimum surface field magnitudes according to the VIP4 model. Between the 8- R j and the 12- R j ovals, the peak brightness occurs at λ III ∼ 215° in the north and at ∼ 25° in the south, consistent with the Satoh et al. (1996) System-III anomalies. These enhancements may originate from the “windshield wiper” effects of drifting electrons, caused by pitch angle scattering of varying efficiency from the inner to the distant magnetosphere. The total power emitted from the entire auroral region by the H + 3 ion at all ro-vibrational levels is estimated as 2.1×10 12 W in the north, and 1.2×10 12 W in the south. Relative contributions from the individual zones are ∼10% from the 6- to 8- R j zone, ∼20% from the 8- to 12- R j zone, ∼25% from the 12- to 30- R j zone, and ∼ 45% from the polar-cap emission, respectively.