Articles | Volume 14, issue 12
Ann. Geophys., 14, 1257–1264, 1996

Special issue: VIIIe EISCAT

Ann. Geophys., 14, 1257–1264, 1996

  31 Dec 1996

31 Dec 1996

Auroral-arc splitting by intrusion of a new convection channel

H. U. Frey1, G. Haerendel1, S. Buchert2, and B. S. Lanchester3 H. U. Frey et al.
  • 1Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr., D-85740 Garching, Germany
  • 2Institut für Geophysik und Meteorologie, TU Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany
  • 3University of Southampton, Department of Physics, Southampton, SO17 1BJ, UK

Abstract. During a run of the Common Programme Three of the EISCAT radar the splitting of an auroral arc was observed by high time-resolution, ground-based cameras when the UHF radar beam was close to the arc. The evening eastward electrojet situation with a large-scale northward ionospheric electric field was disturbed by the intrusion of a convection channel with southward electric field from the east. The interaction of the new convection channel with the auroral arc caused changes in arc brightness and arc splitting, i.e. the creation of a new arc parallel to the pre-existing auroral arc. The event is described as one possibility for the creation of parallel arcs during slightly disturbed magnetic conditions far from the Harang discontinuity.

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