Solar wind control of Jupiter's H-3(+) auroras

A program of observations of Jupiter's H-3(+) auroras was conducted during the first 4 months of 1992, a period that spanned the Ulysses encounter. Daily variations of auroral intensity are small in magnitude (similar to 20%) and well correlated with variations in the solar wind ram pressure arriving at Jupiter, A much larger (factor of 3) time variation is observed to occur on a time scale of approximately 2 months. During the first 2 months of observation, the inferred total intrinsic intensity of the northern aurora exceeded that of the southern aurora by a factor of 2. Throughout the latter 2 months, characterized by less intense auroral activity, the intensity of the northern aurora was comparable to that of the southern aurora. (C) 1996 Academic Press, Inc.