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On the Interactions of Magnetic Fluctuations, Zonal Flows, & Microturbulence in Fusion Plasmas
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | On the Interactions of Magnetic Fluctuations, Zonal Flows, & Microturbulence in Fusion Plasmas. |
| 개인저자 | Williams, Zachary R. |
| 단체저자명 | The University of Wisconsin - Madison. Physics. |
| 발행사항 | [S.l.]: The University of Wisconsin - Madison., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 133 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-03B. Dissertation Abstract International |
| ISBN | 9781085632881 |
| 학위논문주기 | Thesis (Ph.D.)--The University of Wisconsin - Madison, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-03, Section: B.
Advisor: Terry, Paul W. |
| 이용제한사항 | This item must not be sold to any third party vendors.This item must not be added to any third party search indexes. |
| 요약 | A key aspect of turbulent dynamics is the inherent coupling of fluctuations at disparate spatial scales. One significant multi-scale phenomenon is the degradation of zonal flows by large-scale radial magnetic perturbations that result in an increase of small-scale microturbulence and affiliated transport. Two prominent sources of radial magnetic field fluctuations are examined in this thesis, resonant magnetic perturbations (RMPs) in tokamaks and tearing modes in reversed-field pinches (RFPs). This interplay is studied with gyrokinetics to model DIII-D tokamak and MST RFP plasmas. An imposed magnetic perturbation that mimics a tearing mode increases the level of trapped-electron-mode turbulence to a level consistent with fluctuation and transport measurements in MST plasmas. This motivated a dedicated experiment on DIII-D to study the impact of varying RMP amplitude on turbulence in inboard-limited L-mode plasmas. Highlights of the theory-experiment comparison are presented. To study the self-consistent multi-scale interaction of the tearing mode physics, nonlinear simulations containing both tearing mode (driven from equilibrium current gradients) and microinstability scales are performed in a slab geometry. The system is characterized by distinct microinstability- and tearing-dominated regimes. Within the microturbulence-dominated phase, the slow tearing mode growth corresponds directly to a decay in zonal flow. The turbulence levels driven at both large and small scales is increased from single-scale simulations, clearly demonstrated the importance of cross scale interactions. |
| 일반주제명 | Physics. |
| 언어 | 영어 |
| 바로가기 | 
: 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
