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Meridional maps of Saturn's thermal electrons
Author(s) -
Carbary J. F.,
Rymer A. M.
Publication year - 2014
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2013ja019436
Subject(s) - pitch angle , zonal and meridional , physics , electron , equator , flux tube , flux (metallurgy) , field line , saturn , computational physics , asymmetry , plasma , magnetic field , latitude , geophysics , magnetic flux , astrophysics , atmospheric sciences , astronomy , materials science , planet , quantum mechanics , metallurgy
All available observations (July 2004 to June 2011) made by the electron spectrometer (ELS) of the Cassini Plasma Science instrument were used to generate meridional maps of thermal electron fluxes (10–20,000 eV) separated by dayside and nightside. The maps had a spatial resolution of 1 × 1 R S (1 R S = 60,238 km), 10° resolution in pitch angle, and full ELS energy resolution. These maps indicate that electron fluxes tend to accumulate along the field lines between the L shells of ~6 and ~13 in apparent association with the flux tube of Rhea. In the vicinity of Rhea's flux tube, the electrons tend to have field‐aligned pitch angle distributions near the equator, especially between ~10 eV and ~500 eV, but can be isotropic or butterfly at different energies north or south of the equator, and there was no strong evidence of field‐aligned electron pitch angle distributions at higher latitudes. The electron fluxes display strong day‐night asymmetries in flux intensity and pitch angle distribution. However, the day‐night asymmetry observed in the ions, seen as a thicker plasma sheet on the dayside, is not observed in the electrons. Finally, the flux distributions approximately resemble those expected from propagation along field lines using conservation of the first adiabatic invariant.