Auroral electrojets during deep solar minimum at the end of solar cycle 23

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Journal Title
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Volume Title
School of Electrical Engineering | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2011
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Degree programme
Language
en
Pages
10
Series
Journal of Geophysical Research: Space physics, Vol. 116, nro A04207
Abstract
We investigate the auroral electrojet activity during the deep minimum at the end of solar cycle 23 (2008–2009) by comparing data from the IMAGE magnetometer chain, auroral observations in Fennoscandia and Svalbard, and solar wind and interplanetary magnetic field (IMF) observations from the OMNI database from that period with those recorded one solar cycle earlier. We examine the eastward and westward electrojets and the midnight sector separately. The electrojets during 2008–2009 were found to be weaker and at more poleward latitudes than during other times, but when similar driving solar wind and IMF conditions are compared, the behavior in the morning and evening sectors during 2008–2009 was similar to other periods. On the other hand, the midnight sector shows distinct behavior during 2008–2009: for similar driving conditions, the electrojets resided at further poleward latitudes and on average were weaker than during other periods. Furthermore, the substorm occurrence frequency seemed to saturate to a minimum level for very low levels of driving during 2009. This analysis suggests that the solar wind coupling to the ionosphere during 2008–2009 was similar to other periods but that the magnetosphere-ionosphere coupling has features that are unique to this period of very low solar activity.
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Keywords
auroral electrojet, magnetometer chain, solar cycle, solar wind-magnetosphere interaction
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Citation
Pulkkinen, Tuija I. & Tanskanen, E. I. & Viljanen, A. & Partamies, N. & Kauristie, K. 2011. Auroral electrojets during deep solar minimum at the end of solar cycle 23. Journal of Geophysical Research: Space physics, Vol. 116, nro A04207. ISSN 0148-0227 (printed). DOI: 10.1029/2010JA016098.