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Turbulence and Flows in Toroidal Fusion Plasmas
Turbulence and Flows in Toroidal Fusion Plasmas
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20260202104802
- ISBN
- 9798293894437
- DDC
- 530
- 서명/저자
- Turbulence and Flows in Toroidal Fusion Plasmas
- 발행사항
- [Sl] : Princeton University, 2025
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2025
- 형태사항
- 282 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 87-04, Section: B.
- 주기사항
- Advisor: Parra, Felix I.
- 학위논문주기
- Thesis (Ph.D.)--Princeton University, 2025.
- 초록/해제
- 요약Turbulent transport strongly limits the energy confinement of tokamak and stellarator plasmas, posing a major challenge to the development of fusion energy. It is therefore vital to understand the physics of the turbulence underlying this transport and ultimately to identify ways to control it. One crucial mechanism to improve confinement relies on the stabilisation of turbulence through flow shear - arising from either largescale background flows or small-scale zonal flows. In this thesis, I study various ways in which the geometry of tokamaks and stellarators affects turbulence and flows. I show that large-scale flows in quasisymmetric stellarators are more strongly damped than previously realised, both due to centrifugal effects and due to inevitable deviations from perfect quasisymmetry. Motivated by these findings, I present a theory of multiscale gyrokinetics applicable to rotating stellarator plasmas. I also explore how large-scale flows can be optimally driven in non-quasisymmetric stellarators across various collisionality regimes of neoclassical theory. Furthermore, I formulate a theory of the nonlinear dynamics of zonal flows in toroidal geometry, revealing a new type of propagating zonal flow - the toroidal secondary mode. This mode is shown to be essential for the description of zonal flows in nonlinear turbulence simulations and plays a key role in the saturation of strongly-driven ion-temperature-gradient turbulence. Based on critical balance arguments, I use this new zonal flow physics to derive scaling laws for the turbulent heat flux and eddy sizes that are in agreement with gyrokinetic simulations and past experimental observations. Finally, I present a theory of microinstabilities at low magnetic shear, uncovering the physics of a new instability - the geodesic extended mode - which is important for the understanding of turbulence behaviour in optimised stellarators and in tokamaks with reversed magnetic shear.
- 일반주제명
- Plasma physics
- 일반주제명
- Applied physics
- 일반주제명
- Physics
- 키워드
- Flows
- 키워드
- Fusion energy
- 키워드
- Stellarators
- 키워드
- Tokamaks
- 키워드
- Turbulence
- 기타저자
- Princeton University Astrophysical Sciences-Plasma Physics Program
- 기본자료저록
- Dissertations Abstracts International. 87-04B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■00520260202104802
■006m o d
■007cr#unu||||||||
■020 ▼a9798293894437
■035 ▼a(MiAaPQ)AAI32164822
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a530
■1001 ▼aNies, Richard Daniel Caspar.▼0(orcid)0000-0002-9508-1223
■24510▼aTurbulence and Flows in Toroidal Fusion Plasmas
■260 ▼a[Sl]▼bPrinceton University▼c2025
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2025
■300 ▼a282 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 87-04, Section: B.
■500 ▼aAdvisor: Parra, Felix I.
■5021 ▼aThesis (Ph.D.)--Princeton University, 2025.
■520 ▼aTurbulent transport strongly limits the energy confinement of tokamak and stellarator plasmas, posing a major challenge to the development of fusion energy. It is therefore vital to understand the physics of the turbulence underlying this transport and ultimately to identify ways to control it. One crucial mechanism to improve confinement relies on the stabilisation of turbulence through flow shear - arising from either largescale background flows or small-scale zonal flows. In this thesis, I study various ways in which the geometry of tokamaks and stellarators affects turbulence and flows. I show that large-scale flows in quasisymmetric stellarators are more strongly damped than previously realised, both due to centrifugal effects and due to inevitable deviations from perfect quasisymmetry. Motivated by these findings, I present a theory of multiscale gyrokinetics applicable to rotating stellarator plasmas. I also explore how large-scale flows can be optimally driven in non-quasisymmetric stellarators across various collisionality regimes of neoclassical theory. Furthermore, I formulate a theory of the nonlinear dynamics of zonal flows in toroidal geometry, revealing a new type of propagating zonal flow - the toroidal secondary mode. This mode is shown to be essential for the description of zonal flows in nonlinear turbulence simulations and plays a key role in the saturation of strongly-driven ion-temperature-gradient turbulence. Based on critical balance arguments, I use this new zonal flow physics to derive scaling laws for the turbulent heat flux and eddy sizes that are in agreement with gyrokinetic simulations and past experimental observations. Finally, I present a theory of microinstabilities at low magnetic shear, uncovering the physics of a new instability - the geodesic extended mode - which is important for the understanding of turbulence behaviour in optimised stellarators and in tokamaks with reversed magnetic shear.
■590 ▼aSchool code: 0181.
■650 4▼aPlasma physics
■650 4▼aApplied physics
■650 4▼aPhysics
■653 ▼aFlows
■653 ▼aFusion energy
■653 ▼aStellarators
■653 ▼aTokamaks
■653 ▼aTurbulence
■690 ▼a0759
■690 ▼a0215
■690 ▼a0605
■71020▼aPrinceton University▼bAstrophysical Sciences-Plasma Physics Program.
■7730 ▼tDissertations Abstracts International▼g87-04B.
■790 ▼a0181
■791 ▼aPh.D.
■792 ▼a2025
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17358865▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
