Altitude Distribution of the Auroral Acceleration Potential Determined from Cluster Satellite Data at Different Heights
- Space and Plasma Physics, School of Electrical Engineering, KTH, SE 10044 Stockholm (Sweden)
- Swedish Institute of Space Physics, Box 812, SE 981 28 Kiruna (Sweden)
- Mullard Space Science Laboratory, University College, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom)
- Space and Atmospheric Physics Group, Blacket Laboratory, Imperial College, London (United Kingdom)
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242-1479 (United States)
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 R{sub E} 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.
- OSTI ID:
- 21532282
- Journal Information:
- Physical Review Letters, Vol. 106, Issue 5; Other Information: DOI: 10.1103/PhysRevLett.106.055002; (c) 2011 American Institute of Physics; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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