Innes, D. E., D. E. McKenzie, and Tongjiang Wang, Observations of 1000 km s$^-1$ Doppler shifts in 10$^7$ K solar flare supra-arcade, Sol. Phys., 217, 267-279 (2003) (ADS)
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Date: 2019 January 05
Update: 2020 October 30
Several cartoons in the Archive describe SADs, the "supra-arcade downflows" that might result from flux tubes entrained in the super-Alfvénic reconnection outflow expected in a CSHKP flare model. See the McKenzie-Savage or Klimchuk takes on this, for example. Here the authors relate the phenomenon to plasma flows at 800-1000 km/s detected by the SOHO/SUMER instrument in its Fe XXI (hot!) line in the SOL2002-04-21 flare observed by RHESSI as well. This is quite interesting, because most spectroscopic and direct imaging suggest sub-Alfvénic flow speeds for the SADs. The puzzle is that these flows, in the line of sight at the limb, would be horizontal, whereas CSHKP predicts vertical flows.