A Disturbance of the Ion Tail of Comet Halley and the Heliospheric Structure as Observed by Sakigake

  1. Thomas J. Birmingham and
  2. Alexander J. Dessler
  1. Takao Saito1,
  2. Kiyohumi Yumoto1,
  3. Kunio Hirao2,
  4. Keiji Saito3,
  5. Tomoko Nakagawa1 and
  6. Edward J. Smith4

Published Online: 19 MAR 2013

DOI: 10.1029/SP027p0293

Comet Encounters

Comet Encounters

How to Cite

Saito, T., Yumoto, K., Hirao, K., Saito, K., Nakagawa, T. and Smith, E. J. (1988) A Disturbance of the Ion Tail of Comet Halley and the Heliospheric Structure as Observed by Sakigake, in Comet Encounters (eds T. J. Birmingham and A. J. Dessler), American Geophysical Union, Washington, D.C.. doi: 10.1029/SP027p0293

Author Information

  1. 1

    Onagawa Magnetic Observatory, Geophysical Institute, Tohoku University, Sendai 980, Japan

  2. 2

    Department of Aeronautics and Astronautics, Tokai University, Hiratsuka, Kanagawa 259-12, Japan

  3. 3

    Hosei University, Fujimi 2-17-1, Chiyoda-Ku, Tokyo 102, Japan

  4. 4

    Jet Propulsion Laboratory, California Institute of Technologypasadena, CA 91109, USA

Publication History

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

ISBN Information

Print ISBN: 9780875902395

Online ISBN: 9781118668757



  • Cometary magnetosphere;
  • Comet Halley;
  • Disconnection event (DE);
  • Dynamic pressure model;
  • Heliospheric neutral sheet;
  • Ion tail


In order to study the interaction between the solar wind measured by Sakigake and ion tail disturbances of comet Halley, more than 500 photographs of the comet taken on the ground during this apparition are surveyed. The focus of the present study is the December 31, 1985, event, when various types of disturbances occurred, including an outstanding disconnection event (DE)-like knot. Analysis of the Sakigake/IMF data reveals that comet Halley did not encounter the heliospheric neutral sheet on that day, demanding a new explanation for the DE-like event, different from the Niedner-Brandt model. During this event the comet encountered a high-speed solar wind stream from a coronal hole tongue of the sun. The event can be explained by a dynamic pressure model, according to which the DE-like plasmoid was caused by a sudden increase in the dynamic pressure of the solar wind. A result of the simulation work by Ogino is found to support this interpretation.