Observations of high-velocity SAPS-like flows with the King Salmon SuperDARN radar
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).
Koustov, A. V., Drayton, R. A., Makarevich, R. A., McWilliams, K. A., St-Maurice, J.-P., Kikuchi, T., and Frey, H. U.: Observations of high-velocity SAPS-like flows with the King Salmon SuperDARN radar, Ann. Geophys., 24, 1591-1608, doi:10.5194/angeo-24-1591-2006, 2006.