Journal article
Frequency drift of Saturn chorus emission compared to nonlinear theory
Journal of geophysical research. Space physics, Vol.118(3), pp.982-990
03/01/2013
DOI: 10.1002/jgra.50165
Abstract
The fine structure of nonlinear drifting-frequency chorus is observed at Saturn by the Cassini Radio and Plasma Wave Investigation. During a high-inclination orbit in which Cassini is at near-constant L-shell within about 10 degrees of the magnetic equator, moderately intense nonlinear chorus is observed. Cassini observed a region of intense chorus and large bandwidth a few degrees on either side of the magnetic equator, with lower intensities and bandwidths observed nearest the magnetic equator. Using the observed plasma wave spectra and electron phase space distribution, we have measured plasma parameters within or near the chorus generation region and evaluated the theoretical value of the frequency sweep rate, partial derivative f/partial derivative t, based on the nonlinear wave growth theory of Omura et al. and the backward wave oscillator theory of Trakhtengerts. Both theories produce rates that are within a factor of 2 of the observed values, but the nonlinear wave growth theory values are closer to the observations for the cases examined. The work presented is consistent with nonlinear theory in the generation of chorus, but also reveals a distinct region of weaker or linear chorus growth nearest to the magnetic equator at Saturn.
Details
- Title: Subtitle
- Frequency drift of Saturn chorus emission compared to nonlinear theory
- Creators
- J. D. Menietti - University of IowaY. Katoh - Tohoku UniversityG. B. Hospodarsky - University of IowaD. A. Gurnett - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.118(3), pp.982-990
- Publisher
- Amer Geophysical Union
- DOI
- 10.1002/jgra.50165
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 9
- Grant note
- 22684025 / Ministry of Education, Culture, Sports, Science and Technology in Japan; Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Global COE program "Global Education and Research Center for Earth and Planetary Dynamics" of Tohoku University NNX11AM36G / NASA; National Aeronautics & Space Administration (NASA) 1415150 / JPL 23224011 / Grants-in-Aid for Scientific Research; Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT); Japan Society for the Promotion of Science; Grants-in-Aid for Scientific Research (KAKENHI)
- Language
- English
- Date published
- 03/01/2013
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455559202771
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