자료유형  

 학위논문

Control Number  

0017163206

International Standard Book Number  

9798384096573

Dewey Decimal Classification Number  

530

Main Entry-Personal Name  

Coughlin, John B.

Publication, Distribution, etc. (Imprint  

[S.l.] : University of Washington., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

191 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-03, Section: B.

General Note  

Advisor: Shumlak, Uri;Hu, Jingwei.

Dissertation Note  

Thesis (Ph.D.)--University of Washington, 2024.

Summary, Etc.  

요약Plasma dynamics are coupled across microscopic and macroscopic scales by a variety of nonlinear mechanisms. These include repartition of energy due to kinetic microinstabilities, suppression of fluid instabilities by kinetic stabilization effects, and other mechanisms. At the macroscopic scale plasmas are well-described by fluid equations, whose formal validity depends on the long-time regularization of the phase space distribution function by collisions and magnetic gyrotropization. However, accurately capturing multiscale coupling requires multiscale reduced models which are both efficient and accurate in transition regimes. These regimes, where either collisional or magnetic gyrotropic regularization are marginal, are characterized by the ratio of the (collisional or magnetic) mean free path to a characteristic gradient scale length. This work studies two families of reduced plasma models for transition regimes in depth. The first is an asymptotic expansion for Braginskii-type transport coefficients in the so-called drift ordering for low-beta plasmas. The expansion captures leading-order finite Larmor radius effects for arbitrary collisionality. We present a new derivation of this expansion, evaluate its performance numerically, and provide a numerically feasible approximation. The second family of methods is dynamical low-rank (DLR) methods, which are not based on an asymptotic expansion and have the potential to overcome the curse of dimensionality for kinetic equations. We present two novel DLR schemes for plasma kinetic equations with a focus on fluid-kinetic coupling. One is a DLR method that retains low rank in the highly collisional asymptotic limit. The other is a fully locally conservative DLR method for the Vlasov-Dougherty-Fokker-Planck equation which achieves second-order accuracy in time. All discretizations are described in detail and accompanied by numerical results demonstrating the merit of the proposed approach.

Subject Added Entry-Topical Term  

Computational physics.

Subject Added Entry-Topical Term  

Plasma physics.

Subject Added Entry-Topical Term  

Applied mathematics.

Subject Added Entry-Topical Term  

Fluid mechanics.

Index Term-Uncontrolled  

Asymptotic analysis

Index Term-Uncontrolled  

Fluid equations

Index Term-Uncontrolled  

Kinetic equations

Index Term-Uncontrolled  

Low-rank approximation

Index Term-Uncontrolled  

Plasma dynamics

Index Term-Uncontrolled  

Dynamical low-rank

Added Entry-Corporate Name  

University of Washington Applied Mathematics

Host Item Entry  

Dissertations Abstracts International. 86-03B.

Electronic Location and Access  

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Control Number  

joongbu:654953