Spatial variation of 2 μm H 3+ emission in the southern auroral region of Jupiter

Abstract

Observations of the southern auroral spot of Jupiter, made at the CFHT in September 1988, show evidence for spatial variation of the intensities of the 2-μm lines of H 3 +. A sequence of observations around the auroral region shows variation not only in the absolute intensities, but also in the relative intensities, of H 3 + lines. Possible causes for these variations include temperature fluctuations or differing H 3 + ortho/para ratio, possibly caused by spatial inhomogeneity in the ionosphere; precipitation of different kinds of magnetospheric particles; and different particle flux values within the auroral zone. Information on the systematic variation in the H 3 + physical parameters (temperature of atmospheric levels where H 3 + ions exist and ortho/para ratios of H 3 +) is an interesting constraint for future modeling of the infrared aurorae.