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Ann. Geophys., 16, 1322-1331, 1998
www.ann-geophys.net/16/1322/1998/
© European Geosciences Union 1998

Velocity of auroral arcs drifting equatorward from the polar cap

P. J. S. Williams, C. F. del Pozo, I. Hiscock, and R. Fallows
Adran Ffiseg, Prifysgol Cymru Aberystwyth, Ceredigion SY23 3BZ, Wales, UK e-mail: pjw@ aber.ac.uk

Abstract. The drift velocity of an auroral arc is compared with the component of F-region plasma velocity in the same direction for ten cases where the arc is seen to move steadily equatorward for several minutes without any major change in appearance or orientation. In most cases the two velocities are close, but on two occasions the drift velocity of the arc is much higher than the plasma velocity. From the cases studied it appears that during the growth and recovery phase of the substorm cycle the arc moves with a velocity close to the convection velocity, but during the expansion phase this is not the case.

Key words. Magnetospheric physics (auroral phenomena; electric fields; plasma convection)

Full Article (PDF, 407 KB)

Citation: Williams, P. J. S., del Pozo, C. F., Hiscock, I., and Fallows, R.: Velocity of auroral arcs drifting equatorward from the polar cap, Ann. Geophys., 16, 1322-1331, 1998.   Bibtex   EndNote   Reference Manager