Coexisting structures fromhigh- and low-energy precipitation in fine-scale aurora
2015 (English)In: Geophysical Research Letters, ISSN 0094-8276, Vol. 42, no 5, 1290-1296 p.Article in journal (Refereed) Published
High-resolution multimonochromatic measurements of auroral emissions have revealed the first optical evidence of coexisting small-scale auroral features resulting from separate high- and low-energy populations of precipitating electrons on the same field line. The features exhibit completely separate motion and morphology. From emission ratios and ion chemistry modeling, the average energy and energy flux of the precipitation is estimated. The high-energy precipitation is found to form large pulsating patches of 0.1Hz with a 3Hz modulation, and nonpulsating coexisting discrete auroral filaments. The low-energy precipitation is observed simultaneously on the same field line as discrete filaments with no pulsation. The simultaneous structures do not interact, and they drift with different speeds in different directions. We suggest that the high- and low-energy electron populations are accelerated by separate mechanisms, at different distances from Earth. The small-scale structures could be caused by local instabilities above the ionosphere.
Place, publisher, year, edition, pages
2015. Vol. 42, no 5, 1290-1296 p.
aurora, fine-scale structure, multispectral observations, high-energy precipitation, low-energy precipitation, pulsations
IdentifiersURN: urn:nbn:se:kth:diva-165220DOI: 10.1002/2015GL063173ISI: 000351847600002ScopusID: 2-s2.0-84925872747OAI: oai:DiVA.org:kth-165220DiVA: diva2:810155
QC 201505062015-05-062015-04-242015-05-06Bibliographically approved