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Galileo measurements of plasma density in the Io torus
Journal article   Open access   Peer reviewed

Galileo measurements of plasma density in the Io torus

F. Bagenal, F. J. Crary, A. I. F. Stewart, N. M. Schneider, D. A. Gurnett, W. S. Kurth, L. A. Frank and W. R. Paterson
Geophysical research letters, Vol.24(17), pp.2119-2122
09/01/1997
DOI: 10.1029/97GL01254
url
https://doi.org/10.1029/97GL01254View
Published (Version of record) Open Access

Abstract

The measurements of electron density made by the Plasma Wave Subsystem instruments on Galileo during its pass through the torus on December 7th, 1995 are compared with a model based on Voyager 1 measurements made in March 1979. Outside Io's orbit, the plasma densities observed by Galileo are approximately a factor of two higher than the Voyager values. Shortly after crossing Io's orbit, the Galileo density profile dropped sharply and remained at low values for the rest of the inbound leg, suggesting that the ‘ribbon‧ region was either absent or much farther from Jupiter than usual. The peak density on the outbound leg is consistent with Voyager-based predictions for the cold torus in both location (5.1 Rj) and magnitude (950 cm−3). Inside 5 Rj the density dropped sharply to less than 3 cm−3.

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