Lithium Tracer Ion Energisation Observed at Ampte-UKS

  1. Tom Chang,
  2. M. K. Hudson,
  3. J. R. Jasperse,
  4. R. G. Johnson,
  5. P. M. Kintner and
  6. M. Schulz
  1. A. D. Johnstone,
  2. A. J. Coates,
  3. M. F. Smith and
  4. D. J. Rodgers

Published Online: 21 MAR 2013

DOI: 10.1029/GM038p0186

Ion Acceleration in the Magnetosphere and Ionosphere

Ion Acceleration in the Magnetosphere and Ionosphere

How to Cite

Johnstone, A. D., Coates, A. J., Smith, M. F. and Rodgers, D. J. (1986) Lithium Tracer Ion Energisation Observed at Ampte-UKS, in Ion Acceleration in the Magnetosphere and Ionosphere (eds T. Chang, M. K. Hudson, J. R. Jasperse, R. G. Johnson, P. M. Kintner and M. Schulz), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM038p0186

Author Information

  1. Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey, UK

Publication History

  1. Published Online: 21 MAR 2013
  2. Published Print: 1 JAN 1986

ISBN Information

Print ISBN: 9780875900636

Online ISBN: 9781118664216



  • Magnetosphere—Congresses;
  • Ionosphere—Congresses;
  • Ion flow dynamics—Congresses;
  • Space plasmas—Congresses


When AMPTE-IRM released lithium in the solar wind on 20 September 1984 the UKS spacecraft was situated approximately 33km from the release point. As the cloud of neutral lithium expanded past the UKS the first lithium ions were detected at low (∼10eV/q) energies and the solar wind was seen to be decelerated. Further lithium ions were seen for approximately 4 minutes as the neutral cloud expanded further. The acceleration of the newly-born ions in the convection electric field is consistent with a shell-like expansion of the neutral cloud and can be followed until the ions reach Just over twice the solar wind energy/charge.

A comparison between the momentum change in the solar wind and the momentum acquired by the freshly accelerated Lithium ions demonstrates that momentum is conserved locally and the proportion of momentum transmitted along field lines is small. Only a small faction of the energy lost by the solar wind is given to the Lithium ions. The major proportion goes into compression of the magnetic field and heating of electrons.