Journal article
Plasma Observations Near Saturn: Initial Results from Voyager 2
Science (American Association for the Advancement of Science), Vol.215(4532), pp.563-570
01/29/1982
DOI: 10.1126/science.215.4532.563
PMID: 17771279
Abstract
Results of measurements of plasma electrons and positive ions made during the Voyager 2 encounter with Saturn have been combined with measurements from Voyager 1 and Pioneer 11 to define more clearly the configuration of plasma in the Saturnian magnetosphere. The general morphology is well represented by four regions: (i) the shocked solar wind plasma in the magnetosheath, observed between about 30 and 22 Saturn radii (RS) near the noon meridian; (ii) a variable density region between ∼17 RS and the magnetopause; (iii) an extended thick plasma sheet between ∼17 and ∼7 RS symmetrical with respect to Saturn's equatorial plane and rotation axis; and (iv) an inner plasma torus that probably originates from local sources and extends inward from L ≈ 7 to less than L ≈ 2.7 (L is the magnetic shell parameter). In general, the heavy ions, probably O+, are more closely confined to the equatorial plane than H+, so that the ratio of heavy to light ions varies along the trajectory according to the distance of the spacecraft from the equatorial plane. The general configuration of the plasma sheet at Saturn found by Voyager 1 is confirmed, with some notable differences and additions. The "extended plasma sheet," observed between L ≈ 7 and L ≈ 15 by Voyager 1 is considerably thicker as observed by Voyager 2. Inward of L ≈ 4, the plasma sheet collapses to a thin region about the equatorial plane. At the ring plane crossing, L ≈ 2.7, the observations are consistent with a density of O+ of ∼100 per cubic centimeter, with a temperature of ∼10 electron volts. The location of the bow shock and magnetopause crossings were consistent with those previously observed. The entire magnetosphere was larger during the outbound passage of Voyager 2 than had been previously observed; however, a magnetosphere of this size or larger is expected ∼3 percent of the time.
Details
- Title: Subtitle
- Plasma Observations Near Saturn: Initial Results from Voyager 2
- Creators
- H. S Bridge - Massachusetts Institute of TechnologyF Bagenal - Massachusetts Institute of TechnologyJ. W Belcher - Massachusetts Institute of TechnologyA. J Lazarus - Massachusetts Institute of TechnologyR. L McNutt - Massachusetts Institute of TechnologyJ. D Sullivan - Massachusetts Institute of TechnologyP. R Gazis - Massachusetts Institute of TechnologyR. E Hartle - Goddard Space Flight CenterK. W Ogilvie - Goddard Space Flight CenterJ. D Scudder - Goddard Space Flight CenterE. C Sittler - Goddard Space Flight CenterA Eviatar - Department of Atmospheric Sciences, University of California, Los Angeles 90024G. L Siscoe - Department of Atmospheric Sciences, University of California, Los Angeles 90024C. K Goertz - University of IowaV. M Vasyliunas - Max Planck Society
- Resource Type
- Journal article
- Publication Details
- Science (American Association for the Advancement of Science), Vol.215(4532), pp.563-570
- DOI
- 10.1126/science.215.4532.563
- PMID
- 17771279
- ISSN
- 0036-8075
- eISSN
- 1095-9203
- Language
- English
- Date published
- 01/29/1982
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199727302771
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