Experimental Investigation of Ion Response to Propagating Alfvén Waves

离子对传播阿尔文波响应的实验研究

• 批准号: 0611571
• 负责人: EARL SCIME
• 金额: --
• 依托单位: West Virginia University Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0611571&HistoricalAwards=false
• 关键词: Experimental; Investigation; Ion; Response; Propagating

The proposed project concerns a laboratory investigation of ion heating in the acceleration region of the fast solar wind. A number of mechanisms for ion heating in the fast solar wind have been proposed and this project will examine the possibility that the ions are directly heated by ion-cyclotron damping of Alfvn waves or that counter-propagating, low-frequency, Alfvn waves generate a turbulent cascade that heats ions by exciting higher frequency waves that then damp on the ions. The experiments will be performed in a space-relevant, laboratory plasma with sufficient diagnostic capability to investigate the evolution of the ion velocity space distribution function of majority and minority ions as they interact with propagating Alfvn waves, to observe Alfvn waves as they approach and possibly reflect from a strong gradient in the Alfven speed, and detect the generation of a nonlinear cascade if created by the counter-propagating waves. The effects of transverse flow on Alfven wave propagation will also be investigated and hybrid code modeling of the plasma will be performed in parallel with the experiments.The essential intellectual merit of the proposed activity is the performance of controlled laboratory experiments on phenomena that may play a key role in the acceleration and heating of the fast solar wind. Although Alfven wave propagation has been investigated by a number of different laboratory plasma research teams, the effects of plasma inhomogeneities, such as an Alfven speed gradient, and plasma flow have only recently been the subject of experimental attention. By choosing plasma conditions for which theory predicts a clearly defined outcome, the proposed experiments will provide a strong test of the theories now being applied to the acceleration region of the fast solar wind.

拟议的项目涉及快速太阳风加速区域中离子加热的实验室研究。已经提出了快速太阳风中离子加热的多种机制，该项目将研究离子被 Alfvn 波的离子回旋加速器阻尼直接加热的可能性，或者反向传播的低频 Alfvn 波产生湍流级联，通过激发更高频率的波来加热离子，然后对离子进行阻尼。实验将在具有足够诊断能力的空间相关实验室等离子体中进行，以研究多数离子和少数离子与传播的 Alfvn 波相互作用时离子速度空间分布函数的演变，观察 Alfvn 波接近并可能的情况。从阿尔文速度的强梯度反射，并检测由反向传播波产生的非线性级联的生成。还将研究横流对阿尔文波传播的影响，并将与实验并行进行等离子体的混合代码建模。所提出的活动的基本智力优点是对可能发挥作用的现象进行受控实验室实验的表现。在快速太阳风的加速和加热中发挥着关键作用。尽管许多不同的实验室等离子体研究小组都对阿尔文波传播进行了研究，但等离子体不均匀性（例如阿尔文速度梯度和等离子体流）的影响直到最近才成为实验关注的主题。通过选择理论预测明确定义结果的等离子体条件，所提出的实验将为目前应用于快速太阳风加速区域的理论提供强有力的测试。