Probability Distribution Functions of Field Variations, Non-Gaussianity and Intermittency in the Turbulent Solar Wind

湍流太阳风场变化、非高斯性和间歇性的概率分布函数

• 批准号: 0940976
• 负责人: Brigitte Ragot
• 金额: $ 46.97万
• 依托单位: Helio Research
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0940976&HistoricalAwards=false
• 关键词: Probability; Distribution; Functions; Field; Variations

The proposer plans to study solar wind turbulence by applying statistical analysis techniques to ACE, Wind, and Helios 2 spacecraft data. Specifically, she will analyze magnetic field probability distribution functions (PDFs) in order to seek the causes of intermittency and the departures of solar wind plasma structures from Gaussian profiles. She expects to determine whether phase correlation or spectral variability is the main cause of observed non-Gaussian PDFs of magnetic field variations. In this investigation, she will extend her prior calculations and modeling of non-Gaussian PDFs to a broader range of solar wind parameters, testing both random-phase and phase-correlated models. The proposer will thereby produce theoretical predictions of these PDFs, from the largest to the smallest separation scales, and provide definitive tests of the relative impacts of variability and phase correlations on the non-Gaussian nature of such probability distribution functions. The proposer explains that her new model of intermittent turbulence will be valuable for estimating the scattering of solar wind energetic particles and for quantifying the dispersal of solar wind magnetic field lines. She notes that such information is crucial to accurate space weather predictions of solar energetic particle intensities at the Earth. As a female scientist, the proposer is a member of an underrepresented group in solar physics. Therefore, funding this research will contribute to broadening diversity in the field.

提议者计划通过应用统计分析技术对ACE、wind和太阳风2号航天器数据进行研究。具体而言，她将分析磁场概率分布函数（pdf），以寻求间歇性和太阳风等离子体结构偏离高斯分布的原因。她希望确定相位相关或光谱变化是否是观测到的非高斯pdf磁场变化的主要原因。在这项研究中，她将把她之前的计算和非高斯pdf模型扩展到更广泛的太阳风参数范围，测试随机相位和相位相关模型。因此，提议者将产生这些pdf的理论预测，从最大到最小的分离尺度，并提供变异和相位相关性对这种概率分布函数的非高斯性质的相对影响的明确测试。她解释说，她的新间歇性湍流模型将对估计太阳风高能粒子的散射和量化太阳风磁力线的分散有价值。她指出，这些信息对于准确预测地球上太阳高能粒子强度的太空天气至关重要。作为一名女性科学家，提议者是太阳物理学中一个代表性不足的群体的成员。因此，资助这项研究将有助于扩大该领域的多样性。