Studies of Flows, Turbulence and Transport in the Large Plasma Device

宇宙中大多数可见(发光)物质是由等离子体(电离气体)组成的，例如像我们的太阳这样的恒星。这些等离子体中的大多数都被磁场渗透；与这些磁场相关的力往往会限制等离子体。虽然引力是恒星中的主导力量，但在太阳表面的紫外线和软x射线图像中可以看到拱门和日冕环中存在磁约束的证据。等离子体的磁约束在实验室中使用，特别是在聚变能源研究中：托卡马克中的磁场限制热等离子体，以便核聚变能够发生并被用作电源。在实验室或太空中，磁约束并不完美：等离子体(和相关的热)在磁场中泄漏，主要是由于受限等离子体中自发产生的湍流。了解等离子体和热在受限磁场中的这种泄漏或传输，对于基本理解恒星等天体物理等离子体以及有效地产生聚变能量都是重要的。这个项目将利用加州大学洛杉矶分校的实验室实验(大型等离子体设备或LAPD)来研究流动在控制湍流引起的传输中的作用。这个项目的学术价值源于湍流、传输和在大范围等离子体中流动的基本重要性。对输运、湍流和流动之间相互作用的详细研究将对等离子体物理学的一个广泛的子领域产生影响，包括磁约束聚变以及空间和天体物理等离子体物理。该项目的更广泛影响通过研究和教育活动实现。该提案的一个主要重点是培养两名研究生，他们都在攻读博士学位。这项拟议的工作将利用并扩展与劳伦斯利弗莫尔国家实验室合作的现有工作，将实验测量结果与大规模并行计算机模拟的预测进行比较。这一比较工作将有助于建立磁化等离子体中湍流和输运的预测能力。这对于促进我们在各种环境下对基本等离子体过程的理解是重要的，但对于磁聚变能源研究的进展尤其关键。

Most of the visible (light-emitting) matter in the universe is composed of plasma (ionized gas), e.g. stars like our sun. Most of these plasmas are permeated by magnetic fields; the forces associated with these magnetic fields tend to confine plasmas. Although gravity is the dominant force in stars, evidence of magnetic confinement can be found in the arcades and coronal loops that are visible in ultraviolet and soft x-ray images of the surface of our sun. Magnetic confinement of plasmas is used in the laboratory, in particular in fusion energy research: magnetic fields in a tokamak confine hot plasma so that nuclear fusion can occur and be harnessed as a power source. In the lab or in space, magnetic confinement is not perfect: plasma (and associated heat) leak across the magnetic field, primarily due to turbulence that arises spontaneously in confined plasmas. Understanding this leakage, or transport, of plasma and heat across a confining magnetic field is important both for basic understanding of astrophysical plasmas such as stars as well as for enabling the efficient production of fusion energy. This project will investigate the role of flow in controlling transport due to turbulence, making use of a laboratory experiment at UCLA (the Large Plasma Device or LAPD). The intellectual merit of this project stems from the fundamental importance of turbulence, transport, and flows in a wide range of plasmas. A detailed study of the interplay between transport, turbulence and flows will have an impact on a wide range of subfields of plasma physics, including magnetic confinement fusion, and space and astrophysical plasma physics. The broader impacts of this project are realized through both the research and educational activities. A major focus of the proposal is the training of two graduate students, both working toward a PhD. The proposed work will leverage and extend an existing effort in collaboration with Lawrence Livermore National Laboratory to compare experimental measurements to predictions of massively-parallel computer simulations. This comparative effort will help build a predictive capability in turbulence and transport in magnetized plasmas. This is important in advancing our understanding of fundamental plasma processes in a variety of settings, but is especially critical to progress in magnetic fusion energy research.