Sources of rotational signals in Saturn's magnetosphere

Saturn's internal magnetic field is exceptionally symmetric about its rotation axis. Yet local and remotely sensed observations of field and plasma in Saturn's magnetosphere display periodicities close to Saturn's rotation period. In this communication we provide evidence that Saturn&...

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Bibliographic Details
Published in:Journal of Geophysical Research. A. Space Physics 2009-02, Vol.114 (A2), p.n/a
Main Authors: Khurana, Krishan K., Mitchell, Donald G., Arridge, Christopher S., Dougherty, Michele K., Russell, Christopher T., Paranicas, Chris, Krupp, Norbert, Coates, Andrew J.
Format: Article
Language:English
Subjects:
Earth sciences
Earth, ocean, space
Exact sciences and technology
magnetosphere
Saturn
spin periodicity
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Summary:Saturn's internal magnetic field is exceptionally symmetric about its rotation axis. Yet local and remotely sensed observations of field and plasma in Saturn's magnetosphere display periodicities close to Saturn's rotation period. In this communication we provide evidence that Saturn's inner/middle magnetosphere contains semipermanent azimuthal anomalies in the ring current region in the fluxes of energetic charged particles, plasma density, magnetic field, and electrical current with a longitudinal wave number m = 1. We demonstrate that in the presence of these anomalies and a finite solar elevation angle, the solar wind lifts Saturn's magnetosphere asymmetrically in longitude, generating a tilt in the current sheet of Saturn. The current sheet tilt further produces periodicities in Saturn's middle and outer magnetosphere. The ubiquitous nature of the ring current region anomalies and their profound influence on the magnetospheric structure strongly suggest that the period of the Saturn kilometric radiation (SKR) wave power is controlled by them.
ISSN:0148-0227
2156-2202
DOI:10.1029/2008JA013312