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Ring current impoundment of the Io plasma torusA newly discovered feature in the Io plasma formation that may be described as a ramp separating a high-density plasma ledge on its Jupiterward side from the lower-density radially distended Io plasma disc on its anti-Jupiterward side is observed to coincide with a marked inward decrease in the ring current population. The spatial congruency of the counter-directed maximal gradients in both plasma bodies reveals a profound coupling between them. The existence of the ramp requires a local order-of-magnitude reduction in the diffusion coefficient that governs radial mass transport. It is demonstrated that the diminished diffusive efficiency there is caused by strong pressure gradient inhibition of the interchange instability that underlies mass transport. The Io plasma torus, which is defined as the region of strong ultraviolet emissions, is identified as the plasma ledge. The plasma density in the ledge is high and, incidentally therefore, able to emit strongly because it is impounded against rapid, centrifugal expulsion by the inwardly directed pressure of the ring current at its inner edge.
Document ID
19820028813
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Siscoe, G. L.
(California Univ. Los Angeles, CA, United States)
Thorne, R. M.
(California Univ. Los Angeles, CA, United States)
Richardson, J. D.
(California, University Los Angeles, CA, United States)
Bagenal, F.
(California Univ. Los Angeles, CA, United States)
Sullivan, J. D.
(MIT Cambridge, MA, United States)
Eviatar, A.
(California Univ. Los Angeles, CA, United States)
Date Acquired
August 10, 2013
Publication Date
September 30, 1981
Publication Information
Publication: Journal of Geophysical Research
Volume: 86
Subject Category
Lunar And Planetary Exploration
Accession Number
82A12348
Funding Number(s)
CONTRACT_GRANT: NAGW-87
CONTRACT_GRANT: JPL-953733
CONTRACT_GRANT: NAS7-100
Distribution Limits
Public
Copyright
Other

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