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Ann. Geophys., 24, 1591-1608, 2006
www.ann-geophys.net/24/1591/2006/
© European Geosciences Union 2006
Observations of high-velocity SAPS-like flows with the King Salmon SuperDARN radar
A. V. Koustov1, R. A. Drayton1, R. A. Makarevich2, K. A. McWilliams1, J.-P. St-Maurice1, T. Kikuchi3, and H. U. Frey4
1Institute of Space and Atmospheric Studies, University of Saskatchewan, 116 Science Place, Saskatoon, S7N 5E2, Canada
2Department of Physics, La Trobe University, Victoria 3086, Australia
3Solar-Terrestrial Environment Laboratory, University of Nagoya, 3-13 Honohara, Toyokawa, Aichi 442, Japan
4Space Sciences Laboratory, University of California, Berkley, CA 94720-7450, USA
Abstract. In this study, a focused investigation of the potential for the King Salmon
(KS) SuperDARN HF radar to monitor high-velocity flows near the equatorial
edge of the auroral oval is undertaken. Events are presented with
line-of-sight velocities as high as 2km/s, observed roughly along the
L-shell. Statistically, the enhanced flows are shown to be typical for the
dusk sector (16:00–23:00 MLT), and the average velocity in this sector is
larger (smaller) for winter (summer) conditions. It is also demonstrated
that the high-velocity flows can be very dynamical with more localized
enhancements existing for just several minutes. These short-lived
enhancements occur when the luminosity at the equatorial edge of the auroral
oval suddenly decreases during the substorm recovery phase. The short-lived velocity enhancements can be
established because of proton and ion injections into the inner
magnetosphere and low conductance of the ionosphere and not because of
enhanced tail reconnection. This implies that some KS velocity enhancements
have the same origin as subauroral polarization streams (SAPS).
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