| Item type |
学術雑誌論文 / Journal Article(1) |
| 公開日 |
2022-01-24 |
| タイトル |
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|
タイトル |
Nonlinear excitation of subcritical fast ion-driven modes |
| 言語 |
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|
言語 |
eng |
| キーワード |
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|
主題Scheme |
Other |
|
主題 |
subcritical instabilities |
| キーワード |
|
|
主題Scheme |
Other |
|
主題 |
abrupt excitation |
| キーワード |
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|
主題Scheme |
Other |
|
主題 |
kinetic nonlinearity |
| キーワード |
|
|
主題Scheme |
Other |
|
主題 |
geodesic acoustic mode |
| キーワード |
|
|
主題Scheme |
Other |
|
主題 |
EGAM |
| キーワード |
|
|
主題Scheme |
Other |
|
主題 |
energetic particles |
| キーワード |
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|
主題Scheme |
Other |
| 資源タイプ |
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|
資源タイプ識別子 |
http://purl.org/coar/resource_type/c_6501 |
|
資源タイプ |
journal article |
| その他（別言語等）のタイトル |
|
|
その他のタイトル |
亜臨界高速イオン励起モードの非線形励起, 亜臨界高速イオン励起モードの非線形励起 |
| 著者 |
LESUR, M.
ITOH, Kimitaka
IDO, Takeshi
ITOH, Sanae-I.
Kosuga, Yusuke
Sasaki, Makoto
INAGAKI, Shigeru
OSAKABE, Masaki
OGAWA, Kunihoro
SHIMIZU, Akihiro
IDA, Katsumi
the, LHD Experiment Group
|
| 抄録 |
|
|
内容記述タイプ |
Abstract |
|
内容記述 |
In collisionless plasma, it is known that linearly stable modes can be destabilized (subcritically) by the presence of structures in phase-space. The growth of such structures is a nonlinear, kinetic mechanism, which provides a channel for free-energy extraction, different from conventional inverse Landau damping. However, such nonlinear growth requires the presence of a seed structure with a relatively large threshold in amplitude. We demonstrate that, in the presence of another, linearly unstable (supercritical) mode, wave–wave coupling can provide a seed, which can lead to subcritical instability by either one of two mechanisms. Both mechanisms hinge on a collaboration between fluid nonlinearity and kinetic nonlinearity. If collisional velocity diffusion is low enough, the seed provided by the supercritical mode overcomes the threshold for nonlinear growth of phase-space structure. Then, the supercritical mode triggers the conventional subcritical instability. If collisional velocity diffusion is too large, the seed is significantly below the threshold, but can still grow by a sustained collaboration between fluid and kinetic nonlinearities. Both of these subcritical instabilities can be triggered, even when the frequency of the supercritical mode is rapidly sweeping. These results were obtained by modeling the subcritical mode kinetically, and the impact of the supercritical mode by simple wave–wave coupling equations. This model is applied to bursty onset of geodesic acoustic modes in an LHD experiment. The model recovers several key features such as relative amplitude, timescales, and phase relations. It suggests that the strongest bursts are subcritical instabilities, with sustained collaboration between fluid and kinetic nonlinearities. |
| 書誌情報 |
Nuclear Fusion
巻 56,
号 5,
p. 056009,
発行日 2016-04-13
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| 出版者 |
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出版者 |
IOP Publishing |
| 出版者 |
|
|
出版者 |
International Atomic Energy Agency |
| ISSN |
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|
収録物識別子タイプ |
ISSN |
|
収録物識別子 |
00295515 |
| 書誌レコードID |
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|
収録物識別子タイプ |
NCID |
|
収録物識別子 |
AA00759871 |
| DOI |
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関連タイプ |
isVersionOf |
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|
識別子タイプ |
DOI |
|
|
関連識別子 |
10.1088/0029-5515/56/5/056009 |
| 権利 |
|
|
権利情報 |
This is the Accepted Manuscript version of an article accepted for publication in Nuclear Fusion. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/0029-5515/56/5/056009. |
| 情報源 |
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|
関連名称 |
M. Lesur et al 2016 Nucl. Fusion 56 056009 |
| 関連サイト |
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識別子タイプ |
DOI |
|
|
関連識別子 |
https://doi.org/10.1088/0029-5515/56/5/056009 |
|
|
関連名称 |
Publisher version |
| 著者版フラグ |
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出版タイプ |
AM |
|
出版タイプResource |
http://purl.org/coar/version/c_ab4af688f83e57aa |
| NAIS |
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Nucl.Fusion56_pp056009 (963.5 kB)
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