HR: 0830h
AN: SH21B-0156 [PDF]
TI: Cassini UVIS Time-Series Observations of Interplanetary H Lyman-alpha Emissions
AU: * Pryor, W R
EM: wayne.pryor@lasp.colorado.edu
AF: Central Arizona College, 8470 N. Overfield Road, Coolidge, AZ 85228 United States
AU: Stewart, I F
EM: Ian.Stewart@lasp.colorado.edu
AF: LASP/University of Colorado, 1234 Innovation Drive, Boulder, CO 80303 United States
AU: Esposito, L W
EM: larry.esposito@lasp.colorado.edu
AF: LASP/University of Colorado, 1234 Innovation Drive, Boulder, CO 80303 United States
AU: Jouchoux, A
EM: Alain.Jouchoux@lasp.colorado.edu
AF: LASP/University of Colorado, 1234 Innovation Drive, Boulder, CO 80303 United States
AU: McClintock, W E
EM: William.McClintock@lasp.colorado.edu
AF: LASP/University of Colorado, 1234 Innovation Drive, Boulder, CO 80303 United States
AU: Hansen, C J
EM: Candice.J.Hansen@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AU: Ajello, J M
EM: jajello@mail1.jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 United States
AB:
The Cassini Ultraviolet Imaging Spectrograph (UVIS) has been routinely obtaining high signal-to-noise ratio measurements of
interplanetary H Lyman-alpha, H Lyman-beta, and He 58.4 nm emissions during the cruise phase of its mission to Saturn. We
report here on the time-series Lyman-alpha data obtained to date. These data can be compared to a model of the interstellar
H flowing through the heliosphere and illuminated by the Sun. Of particular interest in these data is the presence of
modulations due to the rotation of solar active regions that strongly emit Lyman-alpha radiation. We compare the observed
modulations to those predicted from our model. If the observed modulations are damped compared to the model predictions,
this may be evidence for multiple scattering of solar photons in the heliosphere. The amount of multiple scattering is an
indicator of the heliospheric H density, a quantity that remains poorly constrained. Additional background measurements are
planned for the orbital phase of the Cassini mission (2004-2008).
DE: 7536 Solar activity cycle (2162)
DE: 7549 Ultraviolet emissions
DE: 7837 Neutral particles
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting