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Coulomb thermal properties and stability of the Io plasma torusCoulomb collisional energy exchange rates are computed for a model of the Io plasma torus consisting of newly created pickup ions, a background of thermally degraded intermediary ions, and a population of cooler electrons. The electrons are collisionally heated by both the pickup ions and background ions and are cooled by electron impact excitation of plasma ions which radiate in the EUV. It is found that a relative concentration of S III pickup ions forbidden S III/electrons = 0.1 with a temperature of 340 eV can deliver energy to the electrons at a rate of 3 x 10 to the -13th erg/cu cm per sec, sufficient to power the EUV emissions in the Io torus. The model predicts a background ion temperature Ti of about 53 eV and an electron temperature Te of about 5.5 eV on the basis of steady-state energy balance relations at Coulomb rates. The model also predicts electron temperature fluctuations at the 30 percent level on a time scale of less than 11 hours, consistent with recent observations of this phenomenon.
Document ID
19840031880
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Barbosa, D. D. (California Univ. Los Angeles, CA, United States)
Coroniti, F. V. (California Univ. Los Angeles, CA, United States)
Eviatar, A. (California, University Los Angeles, CA, United States)
Date Acquired
August 12, 2013
Publication Date
November 1, 1983
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 274
ISSN: 0004-637X
Subject Category
LUNAR AND PLANETARY EXPLORATION
Funding Number(s)
CONTRACT_GRANT: NGL-05-007-190
CONTRACT_GRANT: NSF ATM-81-19544
CONTRACT_GRANT: NAGW-87
Distribution Limits
Public
Copyright
Other