Cluster Observations of Quasi-Static Potential Structures Overlapping with Alfvénic Regions
2012 (English)Article in journal (Other academic) Submitted
Results are presented from an equatorward crossing of the Cluster spacecraft through the high-altitude auroral acceleration region, over a system of East-West aligned auroral arcs in the Southern hemisphere auroral oval. The event occurred during quiet geomagnetic conditions during the expansion phase of a weak substorm. Acceleration potential profiles of the quasi-static structures are determined from the particle and field data. The observations reveal a dynamically developing system of small-scale and large-scale quasi-static structures overlapping with Alfvénic regions. Such overlaps are found within the PSBL and inside the Region 2 of downward currents. No density cavities are seen in the overlap regions. Growths of small-scale potential structures were observed in the PSBL and in the middle of Region 2, during the ~1.5 minutes between the Cluster 4 and Cluster 3 passages. During this period, the Alfvénic regions retreated both at the poleward and equatorward oval boundaries, and the large-scale quasi-static potentials intensified.
Place, publisher, year, edition, pages
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:kth:diva-104471OAI: oai:DiVA.org:kth-104471DiVA: diva2:564794
QS 20122012-11-052012-11-052016-04-15Bibliographically approved