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Title: Survey of Magnetosheath Plasma Properties at Saturn and Inference of Upstream Flow Conditions

Abstract

A new Cassini magnetosheath data set is introduced that is based on a comprehensive survey of intervals in which the observed magnetosheath flow was encompassed within the plasma analyzer field of view and for which the computed numerical moments are therefore expected to be accurate. The data extend from 2004 day 299 to 2012 day 151 and comprise 19,155 416-s measurements. In addition to the plasma ion moments (density, temperature, and flow velocity), merged values of the plasma electron density and temperature, the energetic particle pressure, and the magnetic field vector are included in the data set. Statistical properties of various magnetosheath parameters, including dependence on local time, are presented. The magnetosheath field and flow are found to be only weakly aligned, primarily because of a relatively large z-component of the magnetic field, attributable to the field being pulled out of the equatorial orientation by flows at higher latitudes. A new procedure for using magnetosheath properties to estimate the upstream solar wind speed is proposed and used to determine that the amount of electron heating at Saturn's high Mach-number bow shock is ~4% of the dissipated flow energy. The data set is available as an electronic supplement to this paper.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [5]; ORCiD logo [5]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Planetary Science Inst., Tucson, AZ (United States)
  2. Univ. College London (UCL), Surrey (United Kingdom). Mullard Space Science Lab. (MSSL)
  3. Univ. of Southampton (United Kingdom)
  4. Academy of Athens (Greece); National Observatory of Athens (Greece)
  5. Univ. of Michigan, Ann Arbor, MI (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
National Aeronautic and Space Administration (NASA); USDOE
OSTI Identifier:
1423981
Report Number(s):
LA-UR-17-31158
Journal ID: ISSN 2169-9380; TRN: US1801875
Grant/Contract Number:  
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Volume: 123; Journal Issue: 3; Journal ID: ISSN 2169-9380
Publisher:
American Geophysical Union
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Heliospheric and Magnetospheric Physics; Saturn, magnetosheath

Citation Formats

Thomsen, M. F., Coates, A. J., Jackman, C. M., Sergis, N., Jia, X., and Hansen, K. C.. Survey of Magnetosheath Plasma Properties at Saturn and Inference of Upstream Flow Conditions. United States: N. p., 2018. Web. doi:10.1002/2018JA025214.
Thomsen, M. F., Coates, A. J., Jackman, C. M., Sergis, N., Jia, X., & Hansen, K. C.. Survey of Magnetosheath Plasma Properties at Saturn and Inference of Upstream Flow Conditions. United States. doi:10.1002/2018JA025214.
Thomsen, M. F., Coates, A. J., Jackman, C. M., Sergis, N., Jia, X., and Hansen, K. C.. Thu . "Survey of Magnetosheath Plasma Properties at Saturn and Inference of Upstream Flow Conditions". United States. doi:10.1002/2018JA025214.
@article{osti_1423981,
title = {Survey of Magnetosheath Plasma Properties at Saturn and Inference of Upstream Flow Conditions},
author = {Thomsen, M. F. and Coates, A. J. and Jackman, C. M. and Sergis, N. and Jia, X. and Hansen, K. C.},
abstractNote = {A new Cassini magnetosheath data set is introduced that is based on a comprehensive survey of intervals in which the observed magnetosheath flow was encompassed within the plasma analyzer field of view and for which the computed numerical moments are therefore expected to be accurate. The data extend from 2004 day 299 to 2012 day 151 and comprise 19,155 416-s measurements. In addition to the plasma ion moments (density, temperature, and flow velocity), merged values of the plasma electron density and temperature, the energetic particle pressure, and the magnetic field vector are included in the data set. Statistical properties of various magnetosheath parameters, including dependence on local time, are presented. The magnetosheath field and flow are found to be only weakly aligned, primarily because of a relatively large z-component of the magnetic field, attributable to the field being pulled out of the equatorial orientation by flows at higher latitudes. A new procedure for using magnetosheath properties to estimate the upstream solar wind speed is proposed and used to determine that the amount of electron heating at Saturn's high Mach-number bow shock is ~4% of the dissipated flow energy. The data set is available as an electronic supplement to this paper.},
doi = {10.1002/2018JA025214},
journal = {Journal of Geophysical Research. Space Physics},
number = 3,
volume = 123,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2018},
month = {Thu Mar 01 00:00:00 EST 2018}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on March 1, 2019
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Cited by: 1 work
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