Physics of Plasma Confined by a Dipole Magnetic Field

偶极子磁场约束等离子体的物理学

• 批准号: 9111396
• 负责人: Michael Mauel
• 金额: $ 5.5万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-03-15 至 1994-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9111396&HistoricalAwards=false
• 关键词: Physics; Plasma; Confined; Dipole; Magnetic

The proposed work is to conduct and analyze two specific experiments using the newly assembled Collisionless Terrella Experiment (CTX). The results from these experiments will significantly expand our understanding of collisionless particle transport in planetary magnetospheres. They will be used to test basic theories of chaos and transport induced by dynamic and static non-axisymmetric perturbations to a dipole magnetic field. For the first experiment, energetic electrons trapped within the dipole magnetic field will be generated by operating our microwave plasma source so as to directly heat the high-field regions of the dipole. As seen elsewhere, these electrons will become unstable to a spectrum of low-frequency interchange instabilities and induce collisionless radial transport. We will measure the amplitude, frequency, and wavelength of the fluctuations, the condition for the onset of chaos, and the magnitude of the resulting transport. We will also be able to observe marginally-stable pressure profiles and test theories of adiabatic transport. For the second experiment, we will impose a multipolar static perturbation to the energetic electron plasma breaking azimuthal symmetry and destroying conservation of angular momentum. By measuring the decrease in the confinement of the trapped electrons as the magnitude of the perturbation is increased, we will be able to document the conditions leading to three-dimensional chaos. These experiments will be guided and interpreted by numerical and theoretical analysis. By making correlations between laboratory and numerical simulations, we will demonstrate how magnetic fluctuations can induce transport and heating of energetic particles in dipole fields and establish models for similar processes occurring in planetary magnetospheres.

拟议的工作是使用新组装的无碰撞 Terrella 实验（CTX）进行和分析两个具体实验。 这些实验的结果将极大地扩展我们对行星磁层中无碰撞粒子传输的理解。 它们将用于测试偶极子磁场的动态和静态非轴对称扰动引起的混沌和输运的基本理论。 对于第一个实验，将通过操作我们的微波等离子体源来产生捕获在偶极子磁场中的高能电子，从而直接加热偶极子的高场区域。 正如在其他地方所看到的，这些电子对于低频交换不稳定性谱将变得不稳定，并引起无碰撞的径向传输。 我们将测量波动的幅度、频率和波长、混沌开始的条件以及由此产生的传输的幅度。 我们还将能够观察边缘稳定的压力分布并测试绝热传输理论。 对于第二个实验，我们将对高能电子等离子体施加多极静态扰动，打破方位角对称性并破坏角动量守恒。 通过测量随着扰动幅度的增加而被捕获电子的限制的减少，我们将能够记录导致三维混沌的条件。 这些实验将通过数值和理论分析来指导和解释。 通过实验室和数值模拟之间的关联，我们将演示磁涨落如何引起偶极场中高能粒子的传输和加热，并为行星磁层中发生的类似过程建立模型。