Magnetospheric Hydromagnetic Waves: Internal and External Coupling

磁层水磁波：内部和外部耦合

• 批准号: 9622071
• 负责人: Mary Hudson
• 金额: $ 25.5万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-01 至 2000-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9622071&HistoricalAwards=false
• 关键词: Magnetospheric; Hydromagnetic; Waves; Internal; External

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.

该项目的目标是获得对磁层流体磁模式及其与外部和内部自由能源（如环电流）的耦合的定量理解。接下来将研究三个相互关联的领域：(1)磁层内腔模式，(2)场线共振模式的一般性质，以及(3)高能环电流粒子激发内部驱动的场线共振模式。要研究的关键问题是：(1)内磁层中的腔模式结构是什么，人们应该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)是什么控制着场线谐振模式径向结构，(3)是什么导致了漂移-反弹谐振模式的非线性饱和，以及模式对离子运动的自洽效应是什么。采用的方法有：(1)空腔模式研究、偶极子和一般几何中的本征模式分析和MHD模拟；(2)场线共振模式研究、盒型和偶极子几何中的MHD模拟，包括有限拉莫尔半径效应和电离层阻尼；(3)内驱动场线共振模式研究、盒型和偶极子几何中的MHD/陀螺动力学混合模拟。我们的目标是将尚未包含在这些模式研究中的关键物理结合起来。将与航天器数据进行比较，以检验理论预测，并对观测到的波特性和相关的粒子测量产生新的见解。