Tracking patchy pulsating aurora through all-sky images
Pulsating aurora is frequently observed in the evening and morning sector auroral oval. While the precipitating electrons span a wide range of energies, there is increasing evidence that the shape of pulsating auroral patches is controlled by structures in near-equatorial cold plasma; these patc...
| Published in: | Annales Geophysicae |
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| Main Authors: | , , |
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-07-01
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| Online Access: | https://www.ann-geophys.net/35/777/2017/angeo-35-777-2017.pdf |
| Summary: | Pulsating aurora is frequently observed in the evening and morning
sector auroral oval. While the precipitating electrons span a wide range of
energies, there is increasing evidence that the shape of pulsating auroral
patches is controlled by structures in near-equatorial cold plasma; these
patches appear to move with convection, for example. Given the tremendous
and rapidly increasing amount of auroral image data from which the
velocity of these patches can be inferred, it is timely to develop and
implement techniques for the automatic identification of pulsating auroral patch
events in these data and for the automatic determination of the velocity of
individual patches from that data. As a first step towards this, we have
implemented an automatic technique for determining patch velocities from
sequences of images from the Time History of Events and Macroscale Interactions during
Substorms (THEMIS) all-sky imager (ASI) and applied it to many
pulsating aurora events. Here we demonstrate the use of this technique and
present the initial results, including a comparison between ewograms
(east–west keograms) and time series of patch position as determined by the
algorithm. We discuss the implications of this technique for remote sensing
convection in the inner magnetosphere. |
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| ISSN: | 0992-7689 1432-0576 |