The importance of a dark ionosphere for ion heating and auroral arc formation
2000 (English)In: Geophysical Research Letters, ISSN 0094-8276, Vol. 27, no 11, 1635-1638 p.Article in journal (Refereed) Published
We present observations from the Freja Satellite to show that density reductions and ion heating at Freja heights are anticorrelated with solar illumination of the ionosphere. When the ionospheric foot-point of a flux-tube is in shadow, the ambient density is lower, transverse ion energization is more common and more intense, and the associated density cavities are deeper. In combination with the suggestion that the electrons must be accelerated to keV energies to carry an imposed current in a low density auroral cavity, these observations may explain the recent observation that auroras are more common when the ionosphere below is in darkness.
Place, publisher, year, edition, pages
2000. Vol. 27, no 11, 1635-1638 p.
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:umu:diva-85976DOI: 10.1029/2000GL003758OAI: oai:DiVA.org:umu-85976DiVA: diva2:696395