Collaborative Research: Theory and Numerical Simulations of Intermittent Turbulence in Geospace

合作研究：地球空间间歇湍流的理论和数值模拟

• 批准号: 0637400
• 负责人: Tom Chang
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0637400&HistoricalAwards=false
• 关键词: Collaborative; Research; Theory; Numerical; Simulations

This project will quantitatively address the phenomenon of intermittent turbulence in geospace, with particular emphasis placed on the multifractal nature of the plasma fluctuations observed in the magnetotail and plasma sheet. Detailed spectra and other stochastic properties will be deduced and evaluated from first principles both theoretically and numerically. These results will be compared with actual in-situ experimental observations using modern statistical methods. The sporadic and localized interactions of magnetic coherent structures arising from the plasma resonances can be the source for the observed intermittent turbulence in geospace. Power spectra and local intermittency measures using wavelet analyses will be calculated to display the spottiness of the small-scale turbulent fluctuations and the non-uniformity of coarse-grained dissipation that can lead to magnetic topological reconfigurations. The technique of the dynamic renormalization group will be applied to the study of the scaling properties of the multifractal fluctuations. The structure functions and singular spectra will being quantitatively evaluated in detail and compared with the results obtained from actual experimental observations.

该项目将定量地解决地理空间间歇性湍流的现象，特别强调了在磁尾和血浆片中观察到的等离子体波动的多重性质。详细的光谱和其他随机特性将从理论上和数字上从第一原理推导和评估。这些结果将与使用现代统计方法的实际原位实验观察进行比较。由等离子体共振产生的磁相干结构的零星和局部相互作用可能是观察到的地球空间间间湍流的来源。将计算使用小波分析的功率谱和局部间歇性测量，以显示小规模湍流波动的斑点以及粗粒耗散的不均匀性，这可能导致磁性拓扑重构。动态重新归一化组的技术将应用于多重分裂波动的缩放特性的研究。结构函数和奇异光谱将被详细评估，并将其与从实际的实验观察结果获得的结果进行比较。