Studies of Magnetohydrodynamic Turbulence and Turbulence in the Interplanetary Medium

磁流体动力湍流和行星际介质中的湍流研究

• 批准号: 8913627
• 负责人: William Matthaeus
• 金额: $ 43.21万
• 依托单位: Bartol Research Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-08-01 至 1993-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8913627&HistoricalAwards=false
• 关键词: Studies; Magnetohydrodynamic; Turbulence; Interplanetary; Medium

This grant focuses on plasma turbulence in the magnetohydrodynamic (MHD) model, with an emphasis on implications for space plasmas and S/T research. A major continuing goal is the identification and characterization of basic dynamical processes in MHD turbulence. Prior results on incompressible turbulent relaxation processes such as selective decay and dynamic alignment will be extended to three dimensions and generalized to moderately compressible magnetofluids. Further study and application of turbulent reconnection and turbulence driven by large scale velocity shear will be pursued. These turbulence theory studies involve both analytical studies and extensive direct numerical simulations. Study and development of numerical algorithms for compressible turbulence simulations is also undertaken. A second major area of emphasis is the study of turbulence in the interplanetary medium at MHD scales, involving a high degree of interplay with the basic theory and extensive comparisons with observational data. Major undertakings in interplanetary studies include further development of the consequences of nearly incompressible MHD theory, completion and numerical implementation of an analytical model for theory, completion and numerical implementation of an analytical model for the evolution of interplanetary turbulence, including couplings of the local turbulence to large scale gradients, and the further study of dissipation mechanisms acting near ion gyroscales in the solar wind plasma. A third and closely related area of study involves the effects of MHD turbulence on charged particle acceleration and scattering, especially due to induced electric fields. The overall aim is to understand MHD processes and hence interplanetary 'weather'. //

该基金的重点是磁流体动力学（MHD）模型中的等离子体湍流，重点是对空间等离子体和S/T研究的影响。一个主要的持续目标是识别和表征MHD湍流的基本动力学过程。先前关于不可压缩湍流弛豫过程（如选择性衰减和动态对准）的结果将扩展到三维并推广到中等可压缩磁流体。湍流重联和大尺度速度剪切驱动湍流的进一步研究和应用将继续进行。这些湍流理论研究包括分析研究和广泛的直接数值模拟。研究和开发了可压缩湍流模拟的数值算法。第二个重点领域是在MHD尺度上研究行星际介质中的湍流，涉及与基本理论的高度相互作用以及与观测数据的广泛比较。行星际研究的主要工作包括进一步发展几乎不可压缩MHD理论的结果，完成并数值实现理论的解析模型，完成并数值实现行星际湍流演化的解析模型，包括局部湍流与大尺度梯度的耦合，以及太阳风等离子体中离子回旋尺度附近耗散机制的进一步研究。第三个密切相关的研究领域涉及MHD湍流对带电粒子加速和散射的影响，特别是由于感应电场的影响。总体目标是了解MHD过程，从而了解行星际“天气”。//