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Science 23 November 1979:
Vol. 206. no. 4421, pp. 959 - 962
DOI: 10.1126/science.206.4421.959
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Articles

Radio Science with Voyager at Jupiter: Initial Voyager 2 Results and a Voyager 1 Measure of the Io Torus

V. R. ESHLEMAN 1, G. L. TYLER 1, G. E. WOOD 2, G. F. LINDAL 2, J. D. ANDERSON 2, G. S. LEVY 2, and T. A. CROFT 3

1 Center for Radar Astronomy, Stanford University, Stanford, California 94305
2 Jet Propulsion Laboratory, California Institute of Technology, Pasadena 91103
3 SRI International, Menlo Park, California 94025

Voyager 2 radio signals were observed essentially continuously during a grazing occultation of the spacecraft by the southern limb of Jupiter. Intensity data show a classic atmospheric occultation profile and the effects of turbulence and ionospheric focusing and defocusing. No reliable profile of the neutral atmosphere has yet been obtained, primarily because of a combination of large trajectory uncertainties and error multiplication effects associated with the grazing geometry of the Voyager 2 occultation. Analysis of the dispersive ionospheric refraction data yields preliminary profiles for the topside ionosphere at 66.7°S (entry in the evening) and 50.1°S (exit in the morning) that are reversed with respect to corresponding Voyager 1 profiles in terms of plasma concentration at a fixed altitude. Plasma scale heights and temperatures of 880 kilometers, 1200 K and 1040 kilometers, 1600 K were obtained for morning and evening conditions, respectively. Preliminary reduction of the pre-encounter occultation of Voyager 1 by the Io torus yields an average plasma density of about 1000 electrons per cubic centimeter.

Submitted on September 28, 1979


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Ulysses Radio Occultation Observations of the lo Plasma Torus During the Jupiter Encounter.
M. K. Bird, S. W. Asmar, J. P. Brenkle, P. Edenhofer, O. Funke, M. Patzold, and H. Volland (1992)
Science 257, 1531-1535
   Abstract »    PDF »
Voyager Radio Science Observations of Neptune and Triton.
G. L. Tyler, D. N. Sweetnam, J. D. Anderson, S. E. Borutzki, J. K. Campbell, V. R. Eshleman, D. L. Gresh, E. M. Gurrola, D. P. Hinson, N. Kawashima, et al. (1989)
Science 246, 1466-1473
   Abstract »    PDF »
Voyager 2 Radio Science Observations of the Uranian System: Atmosphere, Rings, and Satellites.
G. L. Tyler, G. L. TYLER, D. N. SWEETNAM, J. D. ANDERSON, J. K. CAMPBELL, V. R. ESHLEMAN, D. P. HINSON, G. S. LEVY, G. F. LINDAL, E. A. MAROUF, et al. (1986)
Science 233, 79-84
   Abstract »    PDF »


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