Journal article
Recurrent energization of plasma in the midnight-to-dawn quadrant of Saturn's magnetosphere, and its relationship to auroral UV and radio emissions
Planetary and space science, Vol.57(14-15), pp.1732-1742
12/01/2009
DOI: 10.1016/j.pss.2009.04.002
Abstract
We demonstrate that under some magnetospheric conditions protons and oxygen ions are accelerated once per Saturn magnetosphere rotation, at a preferred local time between midnight and dawn. Although enhancements in energetic neutral atom (ENA) emission may in general occur at any local time and at any time in a Saturn rotation, those enhancements that exhibit a recurrence at a period very close to Saturn's rotation period usually recur in the same magnetospheric location. We suggest that these events result from current sheet acceleration in the 15-20 Rs range, probably associated with reconnection and plasmoid formation in Saturn's magnetotail. Simultaneous auroral observations by the Hubble Space Telescope (HST) and the Cassini Ultraviolet Imaging Spectrometer (UVIS) suggest a close correlation between these dynamical magnetospheric events and dawn-side transient auroral brightenings. Likewise, many of the recurrent ENA enhancements coincide closely with bursts of Saturn kilometric radiation, again pointing to possible linkage with high latitude auroral processes. We argue that the rotating azimuthal asymmetry of the ring current pressure revealed in the ENA images creates an associated rotating field aligned current system linking to the ionosphere and driving the correlated auroral processes. (C) 2009 Elsevier Ltd. All rights reserved.
Details
- Title: Subtitle
- Recurrent energization of plasma in the midnight-to-dawn quadrant of Saturn's magnetosphere, and its relationship to auroral UV and radio emissions
- Creators
- D. G. Mitchell - Johns Hopkins University Applied Physics LaboratoryS. M. Krimigis - Johns Hopkins University Applied Physics LaboratoryC. Paranicas - Johns Hopkins University Applied Physics LaboratoryP. C. Brandt - Johns Hopkins University Applied Physics LaboratoryJ. F. Carbary - Johns Hopkins University Applied Physics LaboratoryE. C. Roelof - Johns Hopkins University Applied Physics LaboratoryW. S. Kurth - University of IowaD. A. Gurnett - University of IowaJ. T. Clarke - Boston UniversityJ. D. Nichols - University of LeicesterJ. -C. Gerard - University of LiègeD. C. Grodent - University of LiègeM. K. Dougherty - Imperial College LondonW. R. Pryor - Central Arizona College
- Resource Type
- Journal article
- Publication Details
- Planetary and space science, Vol.57(14-15), pp.1732-1742
- DOI
- 10.1016/j.pss.2009.04.002
- ISSN
- 0032-0633
- eISSN
- 1873-5088
- Publisher
- Elsevier
- Number of pages
- 11
- Grant note
- HST-GO-10862.01-A / Space Telescope Science Institute Belgian Fund for Scientific Research (FNRS); Fonds de la Recherche Scientifique - FNRS ESA; European Space Agency PP/E000983/1 / STFC; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) PP/E001076/1 / Science and Technology Facilities Council; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) NAS5-97271; NNX07AJ69G / NASA Office of Space Science; National Aeronautics & Space Administration (NASA) 1279973 / National Aeronautics and Space Administration; National Aeronautics & Space Administration (NASA)
- Language
- English
- Date published
- 12/01/2009
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455657102771
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