Magnetospheric Hydromagnetic Waves: Internal and External Coupling

该项目的目标是从数量上了解磁层的磁流模式及其与环电流等外部和内部自由能源的耦合。 三个相互关联的研究领域如下：（1）内磁层腔模式，（2）场线共振模式的一般特性，和（3）激发内驱动场线共振模式的高能环电流粒子。 需要审查的关键问题是：（1）内磁层中的空腔模式结构是什么，人们应该期望在地面和卫星磁数据中看到的频率是什么，以及从外磁层传输的效率是什么，（2）是什么控制了场线谐振模式径向结构，以及（3）是什么导致漂移-反弹谐振模式的非线性饱和，以及该模式对离子运动的自洽效应是什么。 采用的方法是：（1）对于腔模研究，偶极和一般几何中的本征模分析以及MHD模拟，（2）对于场线谐振模研究，盒和偶极几何中的MHD模拟，包括有限拉莫尔半径效应以及电离层阻尼，以及（3）对于内部驱动场线谐振模的研究，箱形和偶极几何中的混合MHD/陀螺动力学模拟。 我们的目标是将尚未包括在这些模式的研究中的关键物理。 将与航天器数据进行比较，以检验理论预测，并对观测到的波的性质和相关的粒子测量产生新的见解。

The objective of this project is to obtain a quantitative understanding of magnetospheric hudromagnetic modes and their coupling to external and internal sources of free energy, such as the ring current. Three interrelated areas of study will be followed: (1) inner magnetospheric cavity modes, (2) general properties of field line resonance modes, and (3) excitation of internally-driven field line resonance modes by energetic ring current particles. Key questions to be examined are: (1) what is the cavity mode structure in the inner magnetosphere and the frequencies one should expect to see in ground and satellite magnetic data and what is the efficiency of transport from the outer magnetosphere, (2) what controls the field line resonant mode radial structure, and (3) what causes the nonlinear saturation of the drift-bounce resonant mode, and what is the self-consistent effect of the mode on ion motion. The methods to be employed are: (1) for the cavity mode study, eigenmode analysis in dipole and general geometry and MHD simulations, (2) for the field line resonance mode study, MHD simulations in box and dipole geometry including finite Larmor radius effects as well as ionospheric damping, and (3) for the study of internally-driven field line resonance modes, hybrid MHD/gyrokinetic simulations in box and dipole geometry. The goal is to incorporate the key physics which has not yet been included in studies of these modes. Comparisons with spacecraft data will be made to test the theoretical predictions and yield new insights into observed wave properties and associated particle measurements.