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020 ▼a 9781085632881
035 ▼a (MiAaPQ)AAI13904292
040 ▼a MiAaPQ ▼c MiAaPQ ▼d 247004
0820 ▼a 530
1001 ▼a Williams, Zachary R.
24510 ▼a On the Interactions of Magnetic Fluctuations, Zonal Flows, & Microturbulence in Fusion Plasmas.
260 ▼a [S.l.]: ▼b The University of Wisconsin - Madison., ▼c 2019.
260 1 ▼a Ann Arbor: ▼b ProQuest Dissertations & Theses, ▼c 2019.
300 ▼a 133 p.
500 ▼a Source: Dissertations Abstracts International, Volume: 81-03, Section: B.
500 ▼a Advisor: Terry, Paul W.
5021 ▼a Thesis (Ph.D.)--The University of Wisconsin - Madison, 2019.
506 ▼a This item must not be sold to any third party vendors.
506 ▼a This item must not be added to any third party search indexes.
520 ▼a 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.
590 ▼a School code: 0262.
650 4 ▼a Physics.
690 ▼a 0605
71020 ▼a The University of Wisconsin - Madison. ▼b Physics.
7730 ▼t Dissertations Abstracts International ▼g 81-03B.
773 ▼t Dissertation Abstract International
790 ▼a 0262
791 ▼a Ph.D.
792 ▼a 2019
793 ▼a English
85640 ▼u http://www.riss.kr/pdu/ddodLink.do?id=T15492531 ▼n KERIS ▼z 이 자료의 원문은 한국교육학술정보원에서 제공합니다.
980 ▼a 202002 ▼f 2020
990 ▼a ***1008102
991 ▼a E-BOOK