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Annales Geophysicae An interactive open-access journal of the European Geosciences Union
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Volume 18, issue 1
Ann. Geophys., 18, 90–98, 2000
© European Geosciences Union 2000
Ann. Geophys., 18, 90–98, 2000
© European Geosciences Union 2000

  31 Jan 2000

31 Jan 2000

Multi-instrument probing of the polar ionosphere under steady northward IMF

S. E. Pryse1, A. M. Smith1, L. Kersley1, I. K. Walker1, C. N. Mitchell1, J. Moen2,*, and R. W. Smith3 S. E. Pryse et al.
  • 1Department of Physics, University of Wales, Aberystwyth, Ceredigion SY23 3BZ, UK
  • E-mail:
  • 2AFRL/VSB (Space), Hanscom AFB, MA 01731-3010, USA
  • 3Geophysics Institute, University of Alaska-Fairbanks, AK99775, USA
  • Correspondence to: S.E. Pryse
  • *On sabbatical leave from Arctic Geophysics, University Courses on Svalbard, N-9170 Longyearbyen, Norway

Abstract. Observations are presented of the polar ionosphere under steady, northward IMF. The measurements, made by six complementary experimental techniques, including radio tomography, all-sky and meridian scanning photometer optical imaging, incoherent and coherent scatter radars and satellite particle detection, reveal plasma parameters consistent with ionospheric signatures of lobe reconnection. The optical green-line footprint of the reconnection site is seen to lie in the sunward plasma convection of the lobe cells. Downstream in the region of softer precipitation the reverse energy dispersion of the incoming ions can be identified. A steep latitudinal density gradient at the equatorward edge of the precipitation identifies the general location of an adiaroic boundary, separating the open field lines of polar lobe cells from the closed field of viscous-driven cells. Enhancements in plasma density to the south of the gradient are interpreted as ionisation being reconfigured as it is thrust against the boundary by the antisunward flow of the viscous cells near noon. Each of the instruments individually provides valuable information on certain aspects of the ionosphere, but the paper demonstrates that taken together the different experiments complement each other to give a consistent and comprehensive picture of the dayside polar ionosphere..

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

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