uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Seasonal dependence and solar wind control of transpolar arc luminosity
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
2008 (English)In: Journal of Geophysical Research, ISSN 0148-0227, Vol. 113, no A8, A08316- p.Article in journal (Refereed) Published
Abstract [en]

The influence of the solar wind and the interplanetary magnetic field (IMF) on the luminosity of transpolar arcs (TPAs) is examined by taking into account seasonal effects. The study focuses on those transpolar arcs that appear after an IMF By sign change during steady northward IMF. It includes 21 northern hemisphere events identified in a previous study from global UV images taken by the Polar spacecraft between 1996 and 2000. Sorting the TPA events by sign of the Earth dipole tilt we find that the TPAs which appear in the dark hemisphere are on average much weaker than TPAs in the sunlit hemisphere. For the dark hemisphere events, no clear correlation between solar wind parameters and TPA luminosity is found. However, in the sunlit hemisphere, a clear dependence on solar wind and IMF conditions is seen. The TPA brightness is strongly influenced by IMF magnitude, northward IMF Bz and solar wind speed. A weak, negative correlation with the ion density is found. The TPA luminosity in the sunlit hemisphere is much more strongly controlled by the magnetic energy flux than by the kinetic energy flux of the solar wind. This explains the absence of transpolar arcs for the two By sign change cases for positive dipole tilts with lowest magnetic energy flux values. The strong influence of the Earth dipole tilt on the transpolar arc luminosity appears due to the dependence of the ionospheric conductivity on solar EUV emissions.

Place, publisher, year, edition, pages
2008. Vol. 113, no A8, A08316- p.
National Category
Physical Sciences
URN: urn:nbn:se:uu:diva-149345DOI: 10.1029/2008JA013086ISI: 000258824700004OAI: oai:DiVA.org:uu-149345DiVA: diva2:404702
Available from: 2011-03-18 Created: 2011-03-18 Last updated: 2011-03-18Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text
By organisation
Swedish Institute of Space Physics, Uppsala Division
In the same journal
Journal of Geophysical Research
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 131 hits
ReferencesLink to record
Permanent link

Direct link