Detection of Cometary Pickup Ions up to 107 km from Comet Halley: Suisei Observation

  1. Thomas J. Birmingham and
  2. Alexander J. Dessler
  1. T. Terasawa1,
  2. T. Mukai1,
  3. W. Miyake2,
  4. M. Kitayama3 and
  5. K. Hirao3

Published Online: 19 MAR 2013

DOI: 10.1029/SP027p0001

Comet Encounters

Comet Encounters

How to Cite

Terasawa, T., Mukai, T., Miyake, W., Kitayama, M. and Hirao, K. (1988) Detection of Cometary Pickup Ions up to 107 km from Comet Halley: Suisei Observation, in Comet Encounters (eds T. J. Birmingham and A. J. Dessler), American Geophysical Union, Washington, D.C.. doi: 10.1029/SP027p0001

Author Information

  1. 1

    Institute of Space and Astronautical Science, Meguro, Tokyo 153, Japan

  2. 2

    Radio Research Laboratories, Koganei, Tokyo 184, Japan

  3. 3

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

Publication History

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

ISBN Information

Print ISBN: 9780875902395

Online ISBN: 9781118668757



  • Cometary pickup ions;
  • Cometocentric solar ecliptic (CSE);
  • Energy spectrum of particles (ESP);
  • Plasma waves;
  • Solar wind


Cometary pickup protons were observed as far as 9.7×106 km away from the cometary nucleus, while the pickup cometary ions of water-group (expected to be mainly O+) were observed as far as 4.0×10 6 km. Observation of these cometary ions is based on the identification of a specific feature in the phase space distribution of ions (ion-pickup shell). We found that the pickup shell is usually filled only partially (∼50%). This observation suggests that the efficiency of the energy diffusion is comparable to that of the pitch angle diffusion. From the spatial asymmetry in the cometary ion density observed between inbound and outbound parts of the spacecraft orbit, it is suggested that there was a difference of a factor of 2–3 between the ion production rates around the inbound and outbound orbit.