Item type |
itemtype_ver1(1) |
公開日 |
2021-12-06 |
タイトル |
|
|
タイトル |
Simultaneous Observation of Two Isolated Proton Auroras at Subauroral Latitudes by a Highly Sensitive All‐Sky Camera and Van Allen Probes |
|
言語 |
en |
著者 |
Nakamura, Kohki
Shiokawa, Kazuo
Otsuka, Yuichi
Shinbori, Atsuki
Miyoshi, Yoshizumi
Connors, Martin
Spence, Harlan
Reeves, Geoff
Funsten, Herbert O.
MacDowall, Robert
Smith, Charles
Wygant, John
Bonnell, John
|
アクセス権 |
|
|
アクセス権 |
open access |
|
アクセス権URI |
http://purl.org/coar/access_right/c_abf2 |
権利 |
|
|
言語 |
en |
|
権利情報 |
© 2021 American Geophysical Union |
内容記述 |
|
|
内容記述 |
Isolated proton auroras (IPAs) appearing at subauroral latitudes are generated by energetic protons precipitating from the magnetosphere through interaction with electromagnetic ion cyclotron (EMIC) waves. An IPA thus indicates the spatial scale and temporal variation of wave-particle interactions in the magnetosphere. In this study, a unique event of simultaneous ground and magnetospheric satellite observations of two IPAs were conducted on March 16, 2015, using an all-sky imager at Athabasca, Canada and Van Allen Probes. The Van Allen Probes observed two isolated EMIC waves with frequencies of ∼1 and 0.4 Hz at L ≈ 5.0 when the satellite footprint crossed over the two IPAs. This suggests that the IPAs were caused by localized EMIC waves. Proton flux at 5–20 keV increased locally when the EMIC waves appeared. Electron flux at energies below ∼500 eV also increased. Temperature anisotropy of the energetic protons was estimated at 1.5–2.5 over a wide L-value range of 3.0–5.2. Electron density gradually decreased from L = 3.5 to 5.4, suggesting that the EMIC wave at L ≈ 5.0 was located in the gradual plasmapause. From these observations, we conclude that the localized IPAs and associated EMIC waves took place because of localized enhancement of energetic proton flux and plasma density structure near the plasmapause. The magnetic field observed by the satellite showed small variation during the wave observation, indicating that the IPAs were accompanied by the weak field-aligned current. |
|
言語 |
en |
|
内容記述タイプ |
Abstract |
出版者 |
|
|
言語 |
en |
|
出版者 |
Wiley |
言語 |
|
|
言語 |
eng |
資源タイプ |
|
|
資源タイプresource |
http://purl.org/coar/resource_type/c_6501 |
|
タイプ |
journal article |
出版タイプ |
|
|
出版タイプ |
VoR |
|
出版タイプResource |
http://purl.org/coar/version/c_970fb48d4fbd8a85 |
関連情報 |
|
|
関連タイプ |
isVersionOf |
|
|
識別子タイプ |
DOI |
|
|
関連識別子 |
https://doi.org/10.1029/2020JA029078 |
収録物識別子 |
|
|
収録物識別子タイプ |
PISSN |
|
収録物識別子 |
2169-9380 |
書誌情報 |
en : Journal of Geophysical Research: Space Physics
巻 126,
号 5,
p. e2020JA029078,
発行日 2021-05
|
ファイル公開日 |
|
|
日付 |
2021-12-06 |
|
日付タイプ |
Available |