Physics of Plasma Confined by a Dipole Magnetic Field

拟议的工作是利用新组装的无碰撞Terrella实验(CTX)来进行和分析两个具体的实验。这些实验的结果将大大扩展我们对行星磁层中无碰撞粒子输运的理解。它们将被用来测试混沌和由动态和静态非轴对称扰动对偶极磁场引起的输运的基本理论。在第一个实验中，通过操作我们的微波等离子体源，将产生捕获在偶极磁场中的高能电子，从而直接加热偶极的高场区。正如在其他地方看到的，这些电子将变得不稳定，对低频交换不稳定谱，并诱导无碰撞的径向传输。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大小。我们还将能够观察到边缘稳定的压力分布和绝热传输的测试理论。在第二个实验中，我们将对高能电子等离子体施加多极静态微扰，破坏方位对称性，破坏角动量守恒。通过测量随着微扰强度的增加，俘获电子的受限程度的降低，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。通过将实验室模拟和数值模拟相关联，我们将演示磁涨落如何诱导偶极场中高能粒子的输运和加热，并为行星磁层中发生的类似过程建立模型。

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.