Electric-Field Discontinuities at Comet Halley During the Vega Encounters

  1. Alan Johnstone
  1. J.G. Trotignon1,
  2. C. Béghin1,
  3. R. Grard2,
  4. A. Pedersen2,
  5. M. Mogilevsky3 and
  6. Y. Mikhailov3

Published Online: 26 MAR 2013

DOI: 10.1029/GM061p0179

Cometary Plasma Processes

Cometary Plasma Processes

How to Cite

Trotignon, J.G., Béghin, C., Grard, R., Pedersen, A., Mogilevsky, M. and Mikhailov, Y. (1991) Electric-Field Discontinuities at Comet Halley During the Vega Encounters, in Cometary Plasma Processes (ed A. Johnstone), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM061p0179

Author Information

  1. 1

    Laboratoire de Physique et Chimie de l'Environnement, Orléans, France

  2. 2

    Space Science Department, Noordwijk, The Netherlands

  3. 3

    Institute of Terrestrial Magnetism, the Ionosphere and Radio-Wave Propagation, Troitsk, USSR

Publication History

  1. Published Online: 26 MAR 2013
  2. Published Print: 1 JAN 1991

ISBN Information

Print ISBN: 9780875900278

Online ISBN: 9781118663660



  • Comets;
  • Space plasmas;
  • Astrophysics


The high-frequency plasma-wave analyser, APV-V, measured strong electric fields when the Vega spacecraft came in the inner coma of comet P/Halley. Several discontinuities were detected in the region from the bow shock crossing to the closest approach to the nucleus, i.e. at cometocentric distances lying between 106 km and about 8,000 km. This paper deals with the electric-field observations in the vicinity of some of these discontinuities: the bow shock, the mystery region, the cometopause and, closer to the nucleus, several sudden changes in the electric-field spectral intensity. The spectral measurements are stressed and an attempt is made to interpret the observations in terms of the plasma and dust environments in the light of recent results.