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Velocity of SuperDARN echoes at intermediate radar ranges
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  • Alexander Koustov,
  • Michael R Luciuk,
  • Robert G Gillies,
  • Sydney Ullrich,
  • Bion Larson,
  • Kathryn A Mcwilliams,
  • Marina Schmidt
Alexander Koustov
University of Saskatchwean

Corresponding Author:[email protected]

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Michael R Luciuk
U of Saskatchewan
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Robert G Gillies
U of Alberta
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Sydney Ullrich
U of Saskatchewan
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Bion Larson
U of Saskacthewan
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Kathryn A Mcwilliams
University of Saskatchewan
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Marina Schmidt
U of Saskatchewan
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Abstract

The study investigates the relationship between SuperDARN HF radar velocities detected at intermediate ranges of 600-100 km from the radar and the plasma drift. Two approaches are implemented. First, a three-hour interval of SuperDARN Rankin Inlet (RKN) radar measurements and Resolute Bay incoherent scatter radar RISR-C measurements in nearly coinciding directions are investigated to show that 1) HF echoes with low velocities (less than 200 m/s) are often detected when drifts are in excess of 1000 m/s, 2) high-velocity HF echoes from the E region have velocities somewhat below the expected values of the ion-acoustic speed of the plasma and the HF velocity does not show a tendency for an increase at the largest drifts, 3) for E region echoes, 12 MHz velocities are slightly larger than those at 10 MHz, and 4) It often occurs that 12 MHz echoes are received from the electrojet heights while 10 MHz echoes are received from the F region heights so that the observed velocities are quite different with the latter reflecting the drift of the plasma. In the second approach, velocities of 10 and 12 MHz RKN echoes are compared for a large data set comprising several months of observations to show that occurrence of 12 MHz low-velocity echoes is fairly common (up to 25% of the time) whenever the flows are fast. Under this condition, the SuperDARN cross polar cap potential is underestimated by ~4 kilovolts.