Articles | Volume 18, issue 7
Ann. Geophys., 18, 782–788, 2000

Special issue: Lance Thomas

Ann. Geophys., 18, 782–788, 2000

  31 Jul 2000

31 Jul 2000

Dayside ionospheric response to changes in IMF polarity: optical and plasma-flow observations

S. E. Pryse, A. M. Smith, and L. Kersley S. E. Pryse et al.
  • Department of Physics, University of Wales, Aberystwyth, SY23 3BZ, UK
  • e-mail:
  • Correspondence to: L. Kersley

Abstract. The response of the dayside ionosphere to changes in polarity of the interplanetary magnetic field was observed by two independent techniques. The signatures were seen in the 630.0 nm red-line emission, measured by a meridian scanning photometer at Ny-Ålesund on Svalbard, and also in the line-of-sight plasma velocities monitored by the Finland CUTLASS SuperDARN radar. A time difference of some 6 to 8 min occurred between the responses of the two techniques, with the flows being first to respond. In the present case study, the longer delay in the optics suggests that ion precipitation controls the auroral emission.

Key words: Ionosphere (ionosphere-magnetosphere interactions) · Magnetospheric physics (magnetosphere-ionosphere interactions; polar cap phenomena)

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