MISC

査読有り
2015年11月

A direct link between chorus emissions and pulsating aurora on timescales from milliseconds to minutes: A case study at subauroral latitudes

JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
  • Mitsunori Ozaki
  • Satoshi Yagitani
  • Kaoru Sawai
  • Kazuo Shiokawa
  • Yoshizumi Miyoshi
  • Ryuho Kataoka
  • Akimasa Ieda
  • Yusuke Ebihara
  • Martin Connors
  • Ian Schofield
  • Yuto Katoh
  • Yuichi Otsuka
  • Naoki Sunagawa
  • Vania K. Jordanova
  • 全て表示

120
11
開始ページ
9617
終了ページ
9631
記述言語
英語
掲載種別
速報,短報,研究ノート等(学術雑誌)
DOI
10.1002/2015JA021381
出版者・発行元
AMER GEOPHYSICAL UNION

A correlation was observed between chorus emissions and pulsating aurora (PA) from observations at Athabasca (L approximate to 4.3) in Canada at 9: 00-9: 20 UT on 7 February 2013, using an electron multiplying charge-coupled device camera and a VLF loop antenna with sampling rates of 110 Hz and 100 kHz, respectively. Pulsating aurora having a quasiperiodic variation in luminosity and a few hertz modulation was observed together with chorus emissions consisting of a group of successive rising-tone elements. The repetition period and modulation frequency of the PA are in good agreement with those of the modulated chorus. After 9: 11 UT, the temporal features of the aurora became aperiodic PA of indistinct modulation. Simultaneously, the rising-tone chorus turned into chorus emissions consisting of numerous rising-tone elements. The equatorial geomagnetic field inhomogeneity calculated using the Tsyganenko 2002 model shows a decreasing trend during the period. This result is consistent with nonlinear wave growth theory having a small geomagnetic field inhomogeneity, which contributes to a decrease in the threshold amplitude to trigger discrete chorus elements. These observations show a close connection between chorus emissions and PA on timescales from milliseconds for generation of discrete chorus elements on the microphysics of wave-particle interaction to minutes for the variations of the geomagnetic field inhomogeneity related with the substorm activity.

リンク情報
DOI
https://doi.org/10.1002/2015JA021381
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000368252100026&DestApp=WOS_CPL
ID情報
  • DOI : 10.1002/2015JA021381
  • ISSN : 2169-9380
  • eISSN : 2169-9402
  • Web of Science ID : WOS:000368252100026

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