Laboratory Studies of Avalanche Transport in Magnetized Plasmas

这个项目的目标是提高我们对等离子体雪崩的理解，等离子体是一种被磁场渗透的电离气体云。雪崩是在物理系统的一个扩展区域引起重大变化的突发事件。虽然这个概念通常与灾难性的“雪崩”联系在一起，但这种普遍现象在自然和人工系统中都广泛存在。雪崩的典型驱动力和能量来源是描述底层系统的参数之一的急剧变化。本项目是对磁场中等离子体温度和密度的陡坡引发的雪崩进行协同实验和理论研究。这是在自然等离子体中普遍遇到的情况，例如在太阳和地球周围的磁场结构中，任何磁聚变装置的设计都必须考虑到这一点。该项目将包括一名研究生，他将获得对现代实验技术的独特视角，并将参与理论和数值模拟工作。迄今为止，关于磁化等离子体中雪崩输运的大部分实验信息都是在为聚变研究设计的设备中获得的。然而，由于这些设备的复杂性，已经证明很难解开该过程的潜在物理机制。该项目旨在通过探索具有可重复、可控雪崩事件的良好定义的等离子体配置的行为，显著扩展实验知识库。实验获得的数据将为自组织临界动力学的作用、流线的形成和演化、流动和流动剪切的影响以及温度和密度的非局部输运的表现提供定量信息。这些主题处于等离子体科学的前沿，是许多正在进行的理论和计算研究的主题。

The goal of this project is to improve our understanding of avalanches in a plasma, a cloud of ionized gas, that is permeated by a magnetic field. Avalanches are sudden events that cause major changes over an extended region of a physical system. Although the concept is commonly associated with catastrophic "snow avalanches", the general phenomenon occurs widely in both natural and artificial systems. A typical driver and source of energy for an avalanche is a sharp change in one of the parameters that describes the underlying system. This project is a synergistic experimental and theoretical study of avalanches triggered by a steep slope in plasma temperature and density across a magnetic field. This is a situation widely encountered in natural plasmas, such as in magnetic field structures on the Sun and around the Earth, and has to be accounted for in any design of a magnetic fusion device. The project will involve a graduate student who will gain a unique perspective on modern experimental techniques and will also participate in theoretical and numerical modeling work.To date, the majority of experimental information about avalanche transport in a magnetized plasma has been obtained in devices designed for fusion studies. However, due to the complexity of these devices, it has proven difficult to unravel the underlying physical mechanisms of the process. This project aims to significantly expand the experimental knowledge base by exploring the behavior of a well-defined plasma configuration that exhibits repeatable, controllable avalanche events. The data obtained in the experiments will provide quantitative information about the role of self-organized criticality dynamics, the formation and evolution of streamers, the effect of flows and flow shear, and the manifestation of nonlocal transport of both temperature and density. These topics are at the frontier of plasma science and are the subject of numerous ongoing theoretical and computational studies.