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Survey of Magnetosheath Plasma Properties at Saturn and Inference of Upstream Flow Conditions
Author(s) -
Thomsen M. F.,
Coates A. J.,
Jackman C. M.,
Sergis N.,
Jia X.,
Hansen K. C.
Publication year - 2018
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2018ja025214
Subject(s) - magnetosheath , computational physics , physics , solar wind , saturn , magnetic field , bow shock (aerodynamics) , mach number , plasma , magnetopause , geophysics , mechanics , astrophysics , shock wave , planet , nuclear physics , quantum mechanics
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 supporting information to this paper.