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2011 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 106, no 5, p. 055002-Article in journal (Refereed) Published
Abstract [en]
Aurora, commonly seen in the polar sky, is a ubiquitous phenomenon occurring on Earth and other solar system planets. The colorful emissions are caused by electron beams hitting the upper atmosphere, after being accelerated by quasistatic electric fields at 1-2 RE altitudes, or by wave electric fields. Although aurora was studied by many past satellite missions, Cluster is the first to explore the auroral acceleration region with multiprobes. Here, Cluster data are used to determine the acceleration potential above the aurora and to address its stability in space and time. The derived potential comprises two upper, broad U-shaped potentials and a narrower S-shaped potential below, and is stable on a 5 min time scale. The scale size of the electric field relative to that of the current is shown to depend strongly on altitude within the acceleration region. To reveal these features was possible only by combining data from the two satellites.
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-30986 (URN)10.1103/PhysRevLett.106.055002 (DOI)000286878500008 ()21405403 (PubMedID)2-s2.0-79551585415 (Scopus ID)
Note
QC 201103172011-03-172011-03-072022-06-24Bibliographically approved