Temporal survey of the Jovian auroral activity with IUE during Galileo G1/G2 orbit
R. Prangé (IAS, France), T. Livengood (University of Maryland), G. Chagnon, T. Fouchet (IAS, France), S. Maurice (OMP, France), S. Budzien (NRL), W. Harris (University of Wisconsin), P. Zarka (Observatoire de Meudon, France), M. Kivelson (UCLA), B. Kurth (University of Iowa)
It has been shown recently (Prangé et al., Icarus, 102, 9289, 1997) that IUE was a good
indicator of the global auroral activity of Jupiter in the FUV. More
than a month of observations (17 August - 25 September 1996) have been
dedicated to the study of Jupiter in correlation with the end of
Galileo's orbit G1 and beginning of orbit G2. One of the goals of
the program was to perform for the first time a quasi-continuous
monitoring of the FUV auroral activity.
We will present the result of these observations, define an "auroral
activity index", and show how it varies with time. Small variations
of 10%-20% are observed on short time scales (<10 hours to 
1
day). Larger variations, by a factor of 2 to 4 occur on timescales
of 5 to 10 days.
These variations will be compared to the solar wind activity, to the
radio auroral activity of Jupiter, and to Galileo measurements taken
during the same period.