Dynamics of the Auroral Oval During Moderate Substorms

K KAURISTIE*, T.I. Pulkkinen, RJ PELLINEN

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Behaviour of the auroral oval during one isolated substorm (15 December, 1982) is studied using DE-1 UV images, DE-2 particle data, and ASC recordings from Kilpisjarvi and Muonio. The observed oval is compared with the statistical oval determined by Feldstein and Starkov. Their model seems to be quite representative during the growth phase but it fails to describe the morning sector widening during the recovery phase. We present initial results of a statistical study concerning the oval boundary movements during moderate magnetic substorms. The study is based on satellite particle data. We divide substorm activity into two categories: 100 <AE <500 and 500 <AE <1000. Very strong substorms are not included, as the AE station chain cannot record them properly. Three substorm phases (growth, expansion, and recovery) are determined from the AE-index. Comparison between our preliminary results and the statistical model developed by Spiro et al. shows that the shape and size of the oval depend significantly on the substorm phase, not only on the level of magnetic activity. Hence the statistical oval models presented earlier in the literature do not adequately represent the oval during all substorm phases.

Original languageEnglish
Pages (from-to)9-17
Number of pages9
JournalGeomagnetizm i aeronomiya
Volume34
Issue number6
Publication statusPublished - 1994
MoE publication typeA1 Journal article-refereed

Keywords

  • CURRENT SHEET
  • TAIL
  • MODEL

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