=====================================================================
==> In this proposal, more time is being requested for PDROSSAR.JUPITER
==> This proposal requests an upgrade from Priority 3 for PDROSSAR.JUPITER
=====================================================================
The observations of Jupiter in the auroral regions, which were selected in the
first period of ISO observations, were devoted to estimating the energetics of
the aurorae of Jupiter in the Northern and Southern regions. In this previous
auroral proposal, equatorial observations had been allocated to priority 3,
and only the auroral observations are being currently scheduled. The interest
in equatorial observations has nevertheless been recently enhanced from new
observations, giving informations which were not available at time of the
first proposal: (1) by the Galileo probe in 1995, demonstrating directly that
a strong atmospheric heating occurs in the high stratosphere (Seiff et al.,
1996), (2) by the first observations by ISO of unexpected CH4 emissions in the
3.3 micron nu-3 band (Encrenaz et al., 1996). The most favoured interpretation
of these observations is that precipitating particles from the magnetosphere
occur also in the equatorial regions, inducing a strong heating. This
equatorial heating could be related to the so-called Hydrogen bulge observed
by Voyager/UVS as a region of enhanced Lyman-alpha emisson. The geometry of
precipitation is very different at the equator, where magnetic field lines are
almost horizontal, and different populations of particles are present; the
search for a relationship between the polar and equatorial energetic particle
input could therefore greatly enhance our knowledge of the interaction between
the magnetosphere and the upper atmosphere of Jupiter, and serve as an
important input to the nearly emerging Jupiter thermospheric global
circulation models. It is therefore asked to upgrade the equatorial
observations of the previous proposals (assigned initially to priority 3) and
to extend these observations by the observations detailed in this proposal,
which would improve the scientific return of the ISO/Jupiter observations.