Wave-like auroras called dunes have been seen drifting at right angles to aurora wavefronts. In this 10-second timelapse video from Rattray, Scotland, from 19:55 to 22:03 UT, 20 January 2016, the dunes can be seen from 19:56 and 21:51 UT drifting toward the left (and slightly toward the top), corresponding to an overall westward (and slightly southward) motion. This time lapse can be used to estimate the drift speed of the wave field during the 20 January 2016 event.
Source: Grandin, et al (2021), AGU Advances
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Produced by AGU by Larry O'Hanlon
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