eV, which is substantially higher than values derived
from in situ observations by Voyager. We compare that result
with Galileo measurements and discuss implications for the
interpretation of other data sets and Io torus models.
The Electron Temperature in the Io Plasma Torus Ribbon derived from the Line Ratio between [SIII] emissions
M. Küppers (LASP, Boulder), K. Jockers (MPAe, Katl.-Lindau, Germany)
In the last week of May 1995 the Io plasma torus was imaged in
different emissions of [SII], [SIII], and [OIII] using the two-channel
focal reducer of the Max-Planck-Institut für Aeronomie attached to
2.2m telescope ot the European Southern Observatory. The presentation
concentrates on observations of the [SIII] lines at 6312Å and
9531Å. Our measurement of the intensity ratio between that two
lines in the Io torus ribbon corresponds to an electron temperature
of 11 eV, which is substantially higher than values derived
from in situ observations by Voyager. We compare that result
with Galileo measurements and discuss implications for the
interpretation of other data sets and Io torus models.