2011 SuperDARN Workshop
Large-Scale SuperDARN observations of a Sub-Auroral Polarization Stream at Mid-Latitudes
L.B.N. Clausen (1), J.B.H. Baker (1), J.M. Ruohoniemi (1), R.A. Greenwald (1), S.G. Shepherd (2), E.R. Talaat (3), W. Bristow (4)
(1) Space@VT, Virginia Tech, Blacksburg, Virginia, USA
(2) Dartmouth College, Hanover, New Hampshire, USA
(3) Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA
(4) University of Alaska Fairbanks, Fairbanks, Alaska, USA
abstract. On April 9th 2011 six SuperDARN radars located at mid-latitudes observed a sub-auroral polarization stream (SAPS) during a period of moderately disturbed conditions (Kp = 3+, Bz = -2 nT). The observations span about 10 hours of magnetic local time and lasted from 0400 UT to 1100 UT. We present POES and DMSP measurements of precipitating particles which allow for the dynamic localization of the auroral oval during the event. These observations show that the SAPS was located just equatorward of the equatorward boundary of the auroral oval and that the location of the flow channel moved with the boundary as the oval expanded due to continuous solar wind driving. Due to the extensive local time coverage we are able to study for the first time the longitudinal variation of flow velocities inside the SAPS channel. Our observations again highlight that the mid-latitude SuperDARN radars provide invaluable scientific data even during non-storm periods.