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Statistical study for ITG turbulent transport in flux-driven tokamak plasmas based on global gyro-kinetic simulation
https://repo.qst.go.jp/records/79219
https://repo.qst.go.jp/records/792196e1ac0dc-1e90-49c6-b2fa-e2fd7be3767d
| Item type | 学術雑誌論文 / Journal Article(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2020-03-06 | |||||
| タイトル | ||||||
| タイトル | Statistical study for ITG turbulent transport in flux-driven tokamak plasmas based on global gyro-kinetic simulation | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | journal article | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Wang, Wei
× Wang, Wei× Kishimoto, Yasuaki× Imadera, Kenji× Liu, Hairui× Li, Jiquan× Yagi, Masatoshi× Wang, Zhengxiong× Wang, Wei× Yagi, Masatoshi |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Flux-driven ion temperature gradient (ITG) turbulence and associated transport regulated by non-local and non-diffusive processes are investigated based on GKNET simulations in a global toroidal geometry. Among these processes, the instantaneous formation of radially extended quasi-coherent structure, which leads to the transport burst, is found to play an important role in causing global profile formation and relaxation. To elucidate the characteristics of such a transport process, we introduce the size probability distribution function (size-PDF) P(S) to analyze heat flux eddies in the real space, with S the eddy size, incorporated with Fourier-based approaches in spectral space. In the size-PDF to the quiescent phase, P(S) is found to be fitted by three piecewise power laws which transitions at two typical sizes S_a and S_b as P∝S^(-2/3) (S≤S_a), P∝S^(-2) (S_a≤S≤S_b), and P∝S^(-4) (S≥S_b), where S_a~50 and S_b~200 in squared gyro-radius unit ρ_i^2 for the system with a⁄ρ_i ~225 (a: the minor radius). On the other hand, the size-PDF in the bursting phase exhibits non-power law irregular humps corresponding to the quasi-coherent structure for S≥S_b reaching to S~1500. Such a coherent structure is ascribed to the spontaneous alignment of smaller scale eddies through phase matching in radial direction, which is classified as a quasi-deterministic process. Resultantly, a large amount of free energy is extracted from the system due to subsequent growth of the event, by which a self-organized profile is established. The coherent structure is then readily disintegrated by self-generated zonal flows, so that the energy is transferred to smaller eddies, by which the quasi-probabilistic transport including SOC type avalanche is induced on the profile. To conclude, the transport is found to be regulated by the mixture of a quasi-deterministic and a probabilistic process, which leads to stiffness and resilience in the profile formation and self-similarity in the relaxation. | |||||
| 書誌情報 |
Nuclear Fusion 巻 60, 号 6, 発行日 2020-03 |
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| 出版者 | ||||||
| 出版者 | IOP(Institute of Physics) Publishing | |||||
| ISSN | ||||||
| 収録物識別子タイプ | ISSN | |||||
| 収録物識別子 | 0029-5515 | |||||
| DOI | ||||||
| 識別子タイプ | DOI | |||||
| 関連識別子 | 10.1088/1741-4326/ab7892 | |||||
| 関連サイト | ||||||
| 識別子タイプ | URI | |||||
| 関連識別子 | https://iopscience.iop.org/article/10.1088/1741-4326/ab7892 | |||||
