HR: 0800h
AN: P51A-1409    [Abstracts]
TI: Auroral Hiss-Like Emissions Observed by Cassini Near the Rings of Saturn
AU: * Xin, L
EM: lei-xin@uiowa.edu
AF: University of Iowa, Dept. of Physics and Astronomy, Iowa City, IA 52242 United States
AU: Gurnett, D A
EM: donald-gurnett@uiowa.edu
AF: University of Iowa, Dept. of Physics and Astronomy, Iowa City, IA 52242 United States
AU: Santolik, O
EM: ondrej.santolik@mff.cuni.cz
AF: Charles University, Faculty of Mathematics and Physics, Prague, CZ-18000 Czech Republic
AU: Kurth, W S
EM: william-kurth@uiowa.edu
AF: University of Iowa, Dept. of Physics and Astronomy, Iowa City, IA 52242 United States
AB: During the Cassini spacecraft pass over the rings of Saturn on July 1, 2004, a well-defined funnel-shaped electric field emission was detected by the plasma wave instrument onboard the spacecraft. The funnel-shaped emission has spectral characteristics that are very similar to a type of whistler-mode emission called `auroral hiss' that is commonly observed in Earth's auroral region. This is the first detection of such emissions at Saturn. Using a dipole magnetic field and a simple electron density model based on the electron density profile measured by Cassini, ray tracing computations have been performed and it is found that the low altitude boundary of the source is located very close to the B ring at a distance near the synchronous rotation point in the rings. At Earth, such auroral hiss emissions are caused by field-aligned low-energy (100 eV to 1 keV) electron beams associated with the auroral current system. The existence of similar emissions originating from near Saturn's rings suggest that an electrodynamic interaction between the rings and Saturn's co-rotating magnetospheric plasma may be driving field-aligned beams and currents similar to those occurring in Earth's auroral regions.
DE: 7871 Waves and instabilities
DE: 5737 Magnetospheres (2756)
DE: 5759 Rings and dust
DE: 2772 Plasma waves and instabilities
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting