Detection of a New “Chemical” Boundary at Comet Halley

  1. Thomas J. Birmingham and
  2. Alexander J. Dessler
  1. K.I. Gringauz1,
  2. T.I. Gombosi2,
  3. M. Tátrallyay2,
  4. M.I. Verigin1,
  5. A.P. Remizov1,
  6. A.K. Richter3,
  7. I. Apáthy2,
  8. I. Szemerey2,
  9. A.V. Dyachkov1,
  10. O.V. Balakina1 and
  11. A.F. Nagy4

Published Online: 19 MAR 2013

DOI: 10.1029/SP027p0161

Comet Encounters

Comet Encounters

How to Cite

Gringauz, K.I., Gombosi, T.I., Tátrallyay, M., Verigin, M.I., Remizov, A.P., Richter, A.K., Apáthy, I., Szemerey, I., Dyachkov, A.V., Balakina, O.V. and Nagy, A.F. (1988) Detection of a New “Chemical” Boundary at Comet Halley, in Comet Encounters (eds T. J. Birmingham and A. J. Dessler), American Geophysical Union, Washington, D.C.. doi: 10.1029/SP027p0161

Author Information

  1. 1

    Space Research Institute, USSR Academy of Sciences, Ul. Profsoyuznaya 88/34, Moscow 117810, USSR

  2. 2

    Central Research Institute for Physics, Hungarian Academy of Sciences, P.O. Box 49, Budapest, Hungary, 1525

  3. 3

    Max-Planck-Institut Für Aeronomie, P.O. Box 20, D-3411, Katlenburg-Lindau, F.R. Germany

  4. 4

    Space Physics Research Laboratory, the University of Michigan, Ann Arbor, Michigan, 48109, USA

Publication History

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

ISBN Information

Print ISBN: 9780875902395

Online ISBN: 9781118668757



  • Cometary ram analyser (CRA);
  • Comet Halley;
  • Electrostatic electron;
  • Plasma;
  • Solar direction analyser (SDA)


Plasma observations near comet Halley indicate that around 1.6×l05km from the nucleus a newly discovered sharp boundary (cometopause) separates the solar wind controlled external and the heavy cometary ion dominated internal regions. Such a discontinuity was previously not predicted by theoretical models. Inside the cometopause (in the cometary plasma region) the protons and heavy ions move with different speeds: the heavy ion velocity is less than a few km/s throughout this region, while the protons decelerate from several tens of km/s (observed near the cometopause) to a few km/s (near 1.5×l04km).