Io's interaction with the plasma torus: Galileo magnetometer report

Science

Volumn 274, Issue 5286, 1996, Pages 396-398

  Kivelson, M G ^a   Khurana, K K ^a   Walker, R J ^a   Warnecke, J ^a   Russell, C T ^a   Linker, J A ^b   Southwood, D J ^c   Polanskey, C ^d  

^a UNIVERSITY OF CALIFORNIA   (United States)

^b SCIENCE APPLICATIONS INTERNATIONAL CORPORATION   (United States)

^c IMPERIAL COLLEGE LONDON   (United Kingdom)

^d CALIFORNIA INSTITUTE OF TECHNOLOGY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ARTICLE; ASTRONOMY; ATMOSPHERE; DENSITY; IONIZATION; MAGNETIC FIELD; PLASMA; PRIORITY JOURNAL; SPACE;

EID: 0029851703     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.274.5286.396     Document Type: Article

References (34)

1. M. G. Kivelson et al., Space Sci. Rev. 60, 357 (1992).
2. M. G. Kivelson et al., Science 273, 337 (1996). Note that the labels on the ordinates of figure 4 are incorrect. The correct ranges on the panels from bottom to top are -2100 to -1100, -500 to 500, and -500 to 500. A corrected figure appeared in the 11 October issue of Science, p. 165.
3. F. Bagenal, J. Geophys. Res. 99, 11043 (1994).
4. J. D. Anderson, W. L. Sjogren, G. Schubert, Science 272, 709 (1996).
5. K. K. Khurana, in preparation.
6. 6 A. The current cited is double that of Table 1 (7) because both Alfvén wings close across lo's vicinity.
7. 6 A. The current cited is double that of Table 1 (7) because both Alfvén wings close across lo's vicinity.
8. 6 A. The current cited is double that of Table 1 (7) because both Alfvén wings close across lo's vicinity.
9. F. M. Neubauer, J. Geophys. Res. 85, 1171 (1980).
10. During the Galileo flyby, the plasma density near lo was larger (9) than that during the Voyager 1 epoch; new simulations will be needed to evaluate the effects of the higher plasma density.
11. L. A. Frank et al., Science 274, 394 (1996).
12. C. K. Goertz, J. Geophys. Res. 85, 2949 (1980).
13. We use the term ionization to include impact ionization and photo-ionization. Pickup refers to both ionization and charge exchange. Charge exchange implies removal of charge from a neutral particle (an ion source) and its transfer to an existing ion (a loss process). Ionization changes the plasma density. Charge exchange changes the energy and momentum of an ion in the plasma but, for like species, does not change the ion density.
14. W. H. Smyth and M. R. Combi, J. Geophys. Res. 96, 22711 (1991); W. H. Smyth, Adv. Space Res. 12, 337 (1992).
15. W. H. Smyth and M. R. Combi, J. Geophys. Res. 96, 22711 (1991); W. H. Smyth, Adv. Space Res. 12, 337 (1992).
16. D. J. Southwood and M. W. Dunlop, Planet. Space Sci. 32, 1079 (1984).
17. J. A. Linker, in Plasma Environments of Non-Magnetic Planets. COSPAR Colloquia 4 (1993), pp. 149-158; "The Interaction of lo with the Plasma Torus," thesis, University of California, Los Angeles (1987); J. A, Linker, M. G. Kivelson, R. J. Walker, Geophys. Res. Lett. 16, 763 (1989).
18. J. A. Linker, in Plasma Environments of Non-Magnetic Planets. COSPAR Colloquia 4 (1993), pp. 149-158; "The Interaction of lo with the Plasma Torus," thesis, University of California, Los Angeles (1987); J. A, Linker, M. G. Kivelson, R. J. Walker, Geophys. Res. Lett. 16, 763 (1989).
19. J. A. Linker, in Plasma Environments of Non-Magnetic Planets. COSPAR Colloquia 4 (1993), pp. 149-158; "The Interaction of lo with the Plasma Torus," thesis, University of California, Los Angeles (1987); J. A, Linker, M. G. Kivelson, R. J. Walker, Geophys. Res. Lett. 16, 763 (1989).
20. The references in (14) show that flow toward the center of the wake continues for several lo radii in the downstream flow.
21. The terms heating and cooling in this context refer to the change of the second moment of the distribution function when ions are introduced into the distribution. In this sense, ions added with perpendicular speeds above the thermal speed heat the plasma.
22. C. T. Russell et al., in preparation.
23. R. L. Smith and N. Brice, J. Geophys. Res. 69, 5029 (1964).
24. D. E. Huddleston and A. D. Johnson, ibid. 97, 12217 (1992).
25. M. A. Moreno, G. Schubert, J, Baumgardner, M. G. Kivelson, D. A. Paige, Icarus 91, 63 (1991); discussion in J. R. Spencer and N. M. Schneider, Annu. Rev. Earth Planet. Sci. 24, 125 (1996).
26. M. A. Moreno, G. Schubert, J, Baumgardner, M. G. Kivelson, D. A. Paige, Icarus 91, 63 (1991); discussion in J. R. Spencer and N. M. Schneider, Annu. Rev. Earth Planet. Sci. 24, 125 (1996).
27. N. M. Schneider et al., Science 253, 1394 (1991).
28. D. E. Shemansky, J. Geophys. Res. 93, 1773 (1988).
29. D. A. Gurnett, W. S. Kurth, A. Roux, S. J. Bolton, C. F. Kennel, Science 274, 391 (1996).
30. A particle pressure of ∼250 nPa (8) at the inbound peak relative to a magnetic pressure decrease of ∼900 nPa.
31. z of 100 to 200 nT are produced by reacceleration of the plasma in the wake.
32. 5K.
33. A. J. Dessler, in Physics of the Jovian Magnetosphere, A. J. Dessler, Ed. (Cambridge Univ. Press, New York, 1983), p. 498.
34. The preparation of the data and diagrams was supported by S. Joy, J. Green, D. Wolkovich, A. Frederick, R. Sadakane, and T. King and R. Silva provided much needed assistance. Design and development of the magnetometer was provided by R. Snare, J. Means, and R George, D. Bindschadler and Y. Mei provided support at the Jet Propulsion Laboratory. We thank F. Bagenal and V. Vasyliunas for providing background on some of the scientific issues that we address here. We also thank the entire Galileo team at the Jet Propulsion Laboratory. The work was partially supported by the Jet Propulsion Laboratory under contract JPL 958694. J.A.L. was supported by NASA under contract NASW 4941. UCLA Institute of Geophysics and Planetary Physics publication number 4650.