Heating of Upflowing Ionospheric Ions on Auroral Field Lines

  1. Tom Chang,
  2. M. K. Hudson,
  3. J. R. Jasperse,
  4. R. G. Johnson,
  5. P. M. Kintner and
  6. M. Schulz
  1. P. H. Reiff1,
  2. H. L. Collin2,
  3. E. G. Shelley2,
  4. J. L. Burch3 and
  5. J. D. Winningham3

Published Online: 21 MAR 2013

DOI: 10.1029/GM038p0083

Ion Acceleration in the Magnetosphere and Ionosphere

Ion Acceleration in the Magnetosphere and Ionosphere

How to Cite

Reiff, P. H., Collin, H. L., Shelley, E. G., Burch, J. L. and Winningham, J. D. (1986) Heating of Upflowing Ionospheric Ions on Auroral Field Lines, 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/GM038p0083

Author Information

  1. 1

    Dept. of Space Physics and Astronomy, Rice University, Houston, Texas 77251

  2. 2

    Lockheed Palo Alto Research Laboratory, Palo Alto, California 94304

  3. 3

    Southwest Research Institute, San Antonio, Texas 78284

Publication History

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

ISBN Information

Print ISBN: 9780875900636

Online ISBN: 9781118664216

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Keywords:

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

Summary

The two coplanar Dynamics Explorer (DE) spacecraft provide a unique opportunity to test for the effects of electric fields aligned parallel to magnetic field lines by sampling, nearly simultaneously, the velocity distribution functions of ions and electrons at two points on the magnetic field lines: DE 1 at high altitudes (9000–15000 km) and DE 2 at low altitudes (400–800 km). The upflowing ion distribution typically can be characterized by a sharp peak and a falloff at high energies of the form exp{(E-Ep)/Eo}, with Ep being the peak energy and Eo a characteristic energy. This is the function that one expects if a Maxwellian of thermal energy Eo is accelerated upwards by a parallel electric field with eΦ = Ep. The acceleration mechanism cannot be a simple parallel electric field, however, for two reasons: first, the characteristic energy Eo is considerably larger than the ionospheric thermal energy (and is typically hundreds of eV - 20–30% of Ep); and secondly, because the energy of the peak Ep is typically 30–50% smaller than would be expected from the potential differences eΦ inferred by two other independent techniques (precipitating electrons at DE 2 and widening of the loss cone for electrons at DE 1). The distribution does appear to be consistent with an ionospheric source, heated within (or above) the acceleration region, since the ion average energy is comparable to eΦ.