Galileo direction finding of Jovian radio emissions

Details Galileo direction finding of Jovian radio emissions Galileo direction finding of Jovian radio emissions

Sep 1998

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998jgr...10320001m&link_type=abstract

Journal of Geophysical Research, Volume 103, Issue E9, p. 20001-20010

Physics

7

Magnetospheric Physics: Planetary Magnetospheres

Scientific paper

The Galileo spacecraft, in orbit about Jupiter, has observed distinct spin modulation of plasma wave emissions near the Ganymede (G1 and G2) encounters in the frequency range from about 100 kHz to approximately 6 MHz. Assuming circularly polarized, transverse electromagnetic radiation, we have used the spin modulation of the sweep-frequency receivers of the electric dipole antenna over many spins to estimate the source location in the spin plane of the spacecraft. Hectometric (HOM) and decametric (DAM) emission is observed by Galileo as a general and continuous background with frequent bursts that last tens of minutes and can be separated by minutes or hours. We have analyzed HOM and DAM emissions observed near Jupiter just after the G1 and G2 encounters, including two HOM/DAM ``arc'' signatures observed after the G2 encounter. These latter appear to be low-frequency extensions of DAM arcs, with source regions along either the Io or the Ganymede flux tube. While the uncertainties associated with the data analysis do not allow a precise source location, the HOM/DAM emission observed near the G1 and G2 encounters is consistent with a gyroresonant source region, but it is necessary to require refraction due to the Io torus to understand the results. To explain emission from apparent source regions above a gyroresonant source region, wave refraction from asymmetries in the Io plasma torus that extend along magnetic field lines is postulated. Alternatively, if such torus density asymmetries do not exist, emission with sources above a gyroresonant source region would require another free-energy source such as energetic plasma beams in the presence of density gradients or temperature anisotropies.

Affiliated with

Also associated with

No associations

Rating

Galileo direction finding of Jovian radio emissions does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Galileo direction finding of Jovian radio emissions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Galileo direction finding of Jovian radio emissions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1711380