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Dawn‐dusk electric field asymmetry of the Io plasma torus
Author(s) -
Barbosa D. D.,
Kivelson M. G.
Publication year - 1983
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/gl010i003p00210
Subject(s) - physics , magnetosphere , electric field , jovian , dusk , plasma , asymmetry , torus , convection , atomic physics , astrophysics , geophysics , astronomy , meteorology , planet , saturn , geometry , mathematics , quantum mechanics
We consider the effects of a combined convection and corotation electric field across the Io plasma torus. A dawn‐to‐dusk electric field E c will modify the orbits of charged particles shifting them toward dawn. The radial drift imposed by the perturbed orbits implies a local time‐dependent modulation of low‐energy ion and electron temperatures with particles hotter at dusk than at dawn. With E c ≃ 4 mV/m, the orbits near 6 R J would be shifted by approximately 0.2 R J . Then the electron temperature would be 20% higher at dusk than at dawn, an effect which could explain the local time asymmetry of EUV intensity found by the Voyager ultraviolet spectrometer. The source of the convection electric field is internal to the magnetosphere and is attributed to the tailward escape of Iogenic and Jovian plasma beyond the Alfven surface.