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A convected K distribution model for hot ions in the Jovian magnetodisc
Author(s) -
Kane M.,
Mauk B. H.,
Keath E. P.,
Krimigis S. M.
Publication year - 1992
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/92gl01610
Subject(s) - jovian , physics , magnetosphere , ion , jupiter (rocket family) , atomic physics , proton , distribution function , plasma , charged particle , solar wind , astrophysics , computational physics , planet , astronomy , saturn , nuclear physics , thermodynamics , spacecraft , quantum mechanics
Hot ion angular anisotropies measured by the Low Energy Charged Particle (LECP) instrument during the Voyager 2 encounter with the Jovian dayside outer magnetosphere (60–30 R J ) have been fitted to a 2 species convected K distribution function using a non‐linear least squares technique. The resulting parameters are well constrained by the data. The heavy ion species was assumed to be either sulfur or oxygen of unknown charge. The light species was assumed to be protons. The bulk flow speeds deduced from the model were found, contrary to some theories, to increase with increasing radial distance from Jupiter within the radial region addressed, remaining a substantial fraction (∼0.6) of the rigid corotation speed. Agreement with the averaged Voyager Plasma Science (PLS) results was obtained near 30 R J . The core Maxwellian temperature of the heavy ion distribution functions (∼30–100 keV) increased with increasing radial distance, following the trend anticipated from the corotation pickup of heavy ions. The proton temperature (∼20 keV) remained nearly constant.