Planetary Magnetodiscs: Some Unanswered Questions

  • Margaret Galland KivelsonEmail author
Part of the Space Sciences Series of ISSI book series (SSSI, volume 50)


Characteristic of giant planet magnetospheres is a near equatorial region in which a radially stretched magnetic field confines a region of high density plasma. The structure, referred to as a magnetodisc, is present over a large range of local time. This introductory chapter describes some of the physics relevant to understanding the formation of this type of structure. Although many features of the magnetodisc are well understood, some puzzles remain. For example, Jupiter’s magnetodisc moves north-south as the planet rotates. The displacement has been attributed to the motion of the dipole equator, but at Saturn the dipole equator does not change its location. This chapter argues that the reasons for flapping may be similar at the two planets and suggests a role for compressional waves in producing the displacement. The development of thermal plasma anisotropy and its role in the structure of Jupiter’s magnetodisc are explored. Finally, localized plasma enhancements encountered by the New Horizons spacecraft at large downtail distances in Jupiter’s nightside magnetodisc are noted and a firehose instability of stretched flux tubes is proposed as a possible interpretation of the observations.


Planetary magnetospheres Plasmas Compressional perturbations Firehose instability 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. M. Ashour-Abdalla, J.P. Berchem, J. Büchner, L.M. Zelenyi, Shaping of the magnetotail from the mantle: Global and local structuring. J. Geophys. Res. 98, 5651–5686 (1993) ADSCrossRefGoogle Scholar
  2. F. Bagenal, Empirical model of the Io plasma torus: Voyager measurements. J. Geophys. Res. 99, 11,043 (1994) ADSCrossRefGoogle Scholar
  3. F. Bagenal, The magnetosphere of Jupiter: Coupling the equator to the poles. J. Atmos. Terr. Phys. 69, 387–402 (2007) ADSCrossRefGoogle Scholar
  4. F. Bagenal, S. Bartlett, (2013)
  5. F. Bagenal, P.A. Delamere, Flow of mass and energy in the magnetospheres of Jupiter and Saturn. J. Geophys. Res. 116, A05209 (2011). doi: 10.1029/2010JA016294 ADSCrossRefGoogle Scholar
  6. F. Bagenal, R.L. McNutt Jr., J.W. Belcher, H.S. Bridge, J.D. Sullivan, Revised ion temperatures for Voyager plasma measurements in the Io plasma torus. J. Geophys. Res. 90(A2), 1755 (1985) ADSCrossRefGoogle Scholar
  7. J.T. Clarke, D. Grodent, S.W.H. Cowley, E.J. Bunce, P. Zarka, J.E.P. Connerney, T. Satoh, Jupiter’s aurora in Jupiter, in The Planet, Satellites and Magnetosphere, ed. by F. Bagenal, T.E. Dowling, W.B. McKinnon (Cambridge University Press, Cambridge, 2004), pp. 639–670. ISBN 0-521-81808-7 Google Scholar
  8. M.E. Davies et al., Report of the IAU/IAG/COSPAR Working Group on Cartographic Coordinates (1996) Google Scholar
  9. I. de Pater, J.J. Lissauer, Planetary Sciences, 2nd edn. (Cambridge Univ. Press, New York, 2010) CrossRefGoogle Scholar
  10. L.A. Frank, W.R. Paterson, Plasmas observed near local noon in Jupiter’s magnetosphere with the Galileo spacecraft. J. Geophys. Res. 109, A11217 (2004). doi: 10.1029/2002JA009795 ADSCrossRefGoogle Scholar
  11. L.A. Frank, W.R. Paterson, K.K. Khurana, Observations of thermal plasmas in Jupiter’s magnetotail. J. Geophys. Res. 107, A11003 (2002). doi: 10.1029/2001JA000077 ADSGoogle Scholar
  12. C.M. Hammond, M.G. Kivelson, R.J. Walker, Imaging the effect of dipole tilt on magnetotail boundaries. J. Geophys. Res. 99, 6079 (1994). (UCLA IGPP Pub. No. 3667), 1993 ADSCrossRefGoogle Scholar
  13. T.W. Hill, Inertial limit on corotation. J. Geophys. Res. 84, 6554 (1979) ADSCrossRefGoogle Scholar
  14. X. Jia, M.G. Kivelson, Driving Saturn’s magnetospheric periodicities from the upper atmosphere/ionosphere: Magnetotail response to dual sources. J. Geophys. Res. 117, A11219 (2012). doi: 10.1029/2012JA018183 ADSGoogle Scholar
  15. X. Jia, M.G. Kivelson, T.I. Gombosi, Driving Saturn’s magnetospheric periodicities from the upper atmosphere/ionosphere. J. Geophys. Res., Atmos. 117, A04215 (2012). doi: 10.1029/2011JA017367 ADSGoogle Scholar
  16. S.P. Joy, M.G. Kivelson, R.J. Walker, K.K. Khurana, C.T. Russell, T. Ogino, Probabilistic models of the Jovian magnetopause and bow shock locations. J. Geophys. Res. 107, A101309 (2002). doi: 10.1029/2001JA009146 ADSCrossRefGoogle Scholar
  17. K.K. Khurana, A generalized hinged-magnetodisc model of Jupiter’s nightside current sheet. J. Geophys. Res. 97, 6269 (1992) ADSCrossRefGoogle Scholar
  18. K.K. Khurana, Eular potential models of Jupiter’s magnetospheric field. J. Geophys. Res. 102, 11,195 (1997) CrossRefGoogle Scholar
  19. K.K. Khurana, H.K. Schwarzl, Global structure of Jupiter’s magnetospheric current sheet. J. Geophys. Res. 110, A07227 (2005). doi: 10.1029/2004JA010757 ADSCrossRefGoogle Scholar
  20. K.K. Khurana, D.G. Mitchell, C.S. Arridge, M.K. Dougherty, C.T. Russell, C. Paranicas, N. Krupp, A.J. Coates, Sources of rotational signals in Saturn’s magnetosphere. J. Geophys. Res. 114, A02211 (2009). doi: 10.1029/2008JA013312 ADSCrossRefGoogle Scholar
  21. M.G. Kivelson, K.K. Khurana, Properties of the magnetic field in the Jovian magnetotail. J. Geophys. Res. 107(A8), 1196 (2002). doi: 10.1029/2001JA000249 CrossRefGoogle Scholar
  22. M.G. Kivelson, D.J. Southwood, Dynamical consequences of two modes of centrifugal instability in Jupiter’s outer magnetosphere. J. Geophys. Res. 110, A12209 (2005). doi: 10.1029/2005JA011176 ADSCrossRefGoogle Scholar
  23. M.G. Kivelson, P.J. Coleman Jr., L. Froidevaux, R.L. Rosenberg, A time dependent model of the Jovian current sheet. J. Geophys. Res. 83, 4823 (1978) ADSCrossRefGoogle Scholar
  24. N. Krupp, A. Lagg, S. Livi, B. Wilken, J. Woch, E.C. Roelof, D.J. Williams, Global flows of energetic ions in Jupiter’s equatorial plane: First-order approximation. J. Geophys. Res. 106, 26,017 (2001) ADSCrossRefGoogle Scholar
  25. B.H. Mauk, S.M. Krimigis, Radial force balance within Jupiter’s dayside magnetosphere. J. Geophys. Res. 92, 9931 (1987) ADSCrossRefGoogle Scholar
  26. D.J. McComas et al., Diverse plasma populations and structures in Jupiter’s magnetotail. Science 318, 217 (2007) ADSCrossRefGoogle Scholar
  27. M. Moncuquet, F. Bagenal, N. Meyer-Vernet, Latitudinal structure of outer Io plasma torus. J. Geophys. Res. 107(A9), 1260 (2002). doi: 10.1029/2001JA900124 CrossRefGoogle Scholar
  28. T.G. Northrop, T.J. Birmingham, Adiabatic charged particle motion in rapidly rotating magnetospheres. J. Geophys. Res. 87(A2), 661–669 (1982) ADSCrossRefGoogle Scholar
  29. T.G. Northrop, C.K. Goertz, M.F. Thomsen, The magnetosphere of Jupiter as observed with Pioneer 10, 2, Nonrigid rotation of the magnetodisc. J. Geophys. Res. 79, 3579 (1974) ADSCrossRefGoogle Scholar
  30. C.P. Paranicas, B.H. Mauk, S.M. Krimigis, Pressure anisotropy and radial stress balance in the jovian neutral sheet. J. Geophys. Res. 96, 21,135 (1991) ADSCrossRefGoogle Scholar
  31. K. Szego, Z. Nemeth, G. Erdos, L. Foldy, M. Thomsen, D. Delapp, The plasma environment of Titan: The magnetodisc of Saturn near the encounters as derived from ion densities measured by the Cassini/CAPS plasma spectrometer. J. Geophys. Res. 116, A10219 (2011). doi: 10.1029/2011JA016629 ADSCrossRefGoogle Scholar
  32. V.M. Vasyliūnas, Plasma distribution and flow, in Physics of the Jovian Magnetosphere, ed. by A.J. Dessler (Cambridge Univ. Press, New York, 1983), p. 395 CrossRefGoogle Scholar
  33. V.M. Vasyliūnas, Role of the plasma acceleration time in the dynamics of the Jovian magnetosphere. Geophys. Res. Lett. 21(6), 401 (1994) ADSCrossRefGoogle Scholar
  34. M.F. Vogt, M.G. Kivelson, K.K. Khurana, R.J. Walker, B. Bonfond, D. Grodent, A. Radioti, Improved mapping of Jupiter’s auroral features to magnetospheric sources. J. Geophys. Res. 116, A03220 (2011). doi: 10.1029/2010JA016148 ADSCrossRefGoogle Scholar
  35. M. Vogt, M.G. Kivelson, K.K. Khurana, R.J. Walker, M. Ashour-Abdalla, Simulating the effect of centrifugal forces in Jupiter’s magnetosphere. J. Geophys. Res. 119, 1925 (2014). doi: 10.1002/2013JA019381 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  1. 1.Department of Earth, Planetary, and Space SciencesUCLALos AngelesUSA
  2. 2.Department of Atmospheric, Oceanic, and Space SciencesUniversity of MichiganAnn ArborUSA

Personalised recommendations