Statics and Dynamics of Giacobini-Zinner Magnetic Tail

  1. Thomas J. Birmingham and
  2. Alexander J. Dessler
  1. G.L. Siscoe1,
  2. J.A. Slavin2,
  3. E.J. Smith2,
  4. B.T. Tsurutani2,
  5. D.E. Jones3 and
  6. D.A. Mendis4

Published Online: 19 MAR 2013

DOI: 10.1029/SP027p0244

Comet Encounters

Comet Encounters

How to Cite

Siscoe, G.L., Slavin, J.A., Smith, E.J., Tsurutani, B.T., Jones, D.E. and Mendis, D.A. (1988) Statics and Dynamics of Giacobini-Zinner Magnetic Tail, in Comet Encounters (eds T. J. Birmingham and A. J. Dessler), American Geophysical Union, Washington, D.C.. doi: 10.1029/SP027p0244

Author Information

  1. 1

    Department of Atmospheric Sciences, University of California, Los Angeles, CA 90024

  2. 2

    Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109

  3. 3

    Department of Physics, Brigham Young University, Provo, UT 94601

  4. 4

    Department of Electrical Engineering and Computer Science, University of California, La Jolla, CA 92093

Publication History

  1. Published Online: 19 MAR 2013
  2. Published Print: 1 JAN 1988

ISBN Information

Print ISBN: 9780875902395

Online ISBN: 9781118668757



  • Axial stress balance;
  • Giacobini-Zinner (G-Z);
  • International Cometary Explorer (ICE);
  • Interplanetary magnetic field (IMF);
  • Transverse pressure balance


We subject the data ICE collected in its traverse of the tail of Giacobini-Zinner to the requirements of stress balance. The result provides estimates for unmeasured quantities. We note that unlike planetary magnetotails, the comet's tail is embedded in an ionosheath that has a static pressure nearly equal to the solar wind stagnation pressure. This leads to a large lobe field strength. Transverse pressure balance reveals a systematic variation in the ion temperature across the tail which in turn tells how the pick-up velocity of new ions varies across the pick-up region. We find the pick-up velocity increases from 14 km s−1 in the plasma sheet to 46 km s−1 in the ionosheath. This is the same velocity shear that stretches the magnetic field to form the tail. Imposing axial stress balance leads to an expression for the strength of the lobe field which reveals that it varies weakly with axial distance. The expression also gives an estimate of 24 km s−1 for the plasma sheet velocity at ICE's location. We find that the plasma takes between 7 and 13 minutes to flow through the coma to the position of ICE in the plasma sheet.