Polar Cusp Electrodynamics–A Case Study

  1. T. E. Moore,
  2. J. H. Waite Jr.,
  3. T. W. Moorehead and
  4. W. B. Hanson
  1. P. E. Sandholt

Published Online: 18 MAR 2013

DOI: 10.1029/GM044p0191

Modeling Magnetospheric Plasma

Modeling Magnetospheric Plasma

How to Cite

Sandholt, P. E. (1988) Polar Cusp Electrodynamics–A Case Study, in Modeling Magnetospheric Plasma (eds T. E. Moore, J. H. Waite, T. W. Moorehead and W. B. Hanson), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM044p0191

Author Information

  1. Institute of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo 3, Norway

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1988

ISBN Information

Print ISBN: 9780875900704

Online ISBN: 9781118664414



  • Space plasmas—Mathematical models;
  • Magnetosphere—Mathematical models;
  • Ionosphere—Mathematical models


Combined satellite and ground-based observations provided the basis for investigating the electrodynamics associated with auroral structures within the polar cusp. A ˜ 45-km-wide structure of enhanced electron precipitation with peak energy flux ˜5 erg cm−2 s−1 (5×10−3 w m−2) and average energy ˜0.1 keV was observed to be associated with a strong, red-dominated auroral arc (I 630.0 nm ≃ 8 kR) with typical spectral ratio I 630.0 nm/I 557.7 nm ≃ 5. Within this arc the northward electric field component reached a peak value of ˜175 mV m−1. A pair of field-aligned currents was observed, with downward current at the arc equatorward boundary and upward current further north. From correlated variations in electric and magnetic field components, the height-integrated Pedersen conductivity and joule heat dissipation rate within the auroral form could be estimated. The joule heat dissipation in the center of the structure was found to be ˜5 times the particle energy input rate.