Stuttgart 2012 – wissenschaftliches Programm
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EP: Fachverband Extraterrestrische Physik
EP 15: Planeten und kleine Körper II
EP 15.3: Vortrag
Donnerstag, 15. März 2012, 11:30–11:45, V55.02
New type of periodic bursts of Jovian non-Io DAM and its relation to interchange instability in the Io plasma torus — •M. Panchenko1, H.O. Rucker1, and W.M. Farrell2 — 1Space Research Institute, Austrian Academy of Sciences, Graz, Austria — 2NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
The radio instruments onboard Cassini, Wind and STEREO spacecraft have recorded a new type of the periodic radio bursts of the Jovian decametric radio emission (DAM). These bursts, which are attributed to the non-Io component of DAM, are observed in a decametric frequency range of dynamic spectra as a series of reoccurring arc-like radio bursts with a period ~1.5% longer than the rotation rate of the planet's magnetosphere. The stereoscopic multispacecraft observations have shown that the radio sources of the periodic bursts radiate in a non-axisymmetric hollow cone-like pattern and sub-corotate with Jupiter, being active during several Jupiter rotations. In this study we investigate the relations between the occurrence of the non-Io DAM periodic bursts and VLF components of the Jovian radiation and solar wind activity at Jupiter. We discuss that the sources of the non-Io DAM periodic bursts which are located in the auroral regions of the Jovian magnetosphere may be connected with the ends of plasma fingers in the Io torus. These latitudinal extended and nearly sub-corotating plasma fingers can be developed in course of the strong interchange instability which may operate along the outer Io torus edge. The interchange instability in the Io plasma torus can be triggered by the strong solar wind impulses.