Journal article
Cassini observation of Jovian anomalous continuum radiation
Journal of geophysical research. Space physics, Vol.117(A4), A04211
04/2012
DOI: 10.1029/2011JA017135
Abstract
Jovian anomalous continuum is a narrowband electromagnetic radiation near 10 kHz that can escape from Jupiter's magnetosphere to interplanetary space. One possible source mechanism is the magnetosheath re-radiation of the Jovian low frequency radio emissions such as the quasiperiodic (QP) radio emissions, broadband kilometric radiation (bKOM) and non-thermal continuum. Jovian anomalous continuum was consistently observed by the Cassini Radio and Plasma Wave Science instrument from 2000 to 2004, right before the Saturn orbit insertion, which means the radiation can be detected as far as 8 AU away from Jupiter. An analysis of intensity versus radial distance shows that the Jovian anomalous continuum has a line source rather than a point source, consistent with the theory that the emission is radiated by the whole length of the magnetotail. The emissions are modulated at the system III period of Jupiter and are unpolarized. Since the lower cutoff frequency of the anomalous continuum is related to the plasma frequency in the magnetosheath of Jupiter, which is a function of solar wind density, the recurrent variations of the lower cutoff frequency can be used as a remote diagnostic of the solar wind condition at Jupiter. We propose that the frequency dispersion, a unique characteristic of the anomalous continuum, is likely a comprehensive effect of both the slow group velocity near the local plasma frequency and the refraction/scattering of the waves by density structures as they propagate in the magnetosheath.
Details
- Title: Subtitle
- Cassini observation of Jovian anomalous continuum radiation
- Creators
- Sheng-Yi Ye - Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USAD. A. Gurnett - Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USAJ. D. Menietti - Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USAW. S. Kurth - Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USAG. Fischer - Austrian Acad Sci, Space Res Inst, A-8042 Graz, AustriaP. Schippers - University of IowaG. B. Hospodarsky - Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.117(A4), A04211
- Publisher
- Amer Geophysical Union
- DOI
- 10.1029/2011JA017135
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 15
- Grant note
- 1279973 / Jet Propulsion Laboratory NASA; National Aeronautics & Space Administration (NASA)
- Language
- English
- Date published
- 04/2012
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455362402771
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