黄狮勇博士学术报告海报

来源：南昌大学科技处、空间研究院 2014/7/1

报告题目:The effects of Taylor hypothesis in solar wind turbulent spectra (泰勒假设对太阳风湍流谱的影响)

 

报 告 人: 黄狮勇 博士 Laboratoire de Physique des Plasmas (France)

报告时间：7月2日上午9:30-11：30

报告地点：空间科学与技术研究院二楼会议室

 

        报告人简介：2013年6月毕业于武汉大学空间物理专业，现在法国国家科学研究中心等离子体实验室从事博士后研究。主要从事空间等离子体中磁场重联和湍流的研究，现已获得多项重要成果，发表SCI论文二十余篇，其中在《Geophys. Res. Lett.》,《J. Geophys. Res.》和《The Astrophysical Journal Letters》等上发表第一作者论文7篇。

        报告摘要: Solar wind is a natural laboratory for the study of turbulent plasma. In-situ observations from different spacecraft, such STEREO, Wind, ACE, Cluster etc., provide good opportunity to investigate turbulence from magnetohydrodynamic (MHD) scale to kinetic scale, even up to electron scale. Taylor hypothesis is usually used to transfer the frequency spectrum into wavenumber spectrum for single spacecraft observations in the turbulence study. In this presentation, we will introduce the effects of Taylor hypothesis in solar wind turbulent spectra. Firstly, we use one simple method to test the validity of Taylor hypothesis in the solar wind turbulence. It is found that not all observational points are strictly satisfied the Taylor hypothesis. Assumed whistler modes carried down the turbulence cascade from ion to electron scale, quantitative analysis indicates that one part of events (24%) approximately satisfy the Taylor hypothesis, but some events have wave phase velocity in the high frequency approach or comparable to the solar wind plasma flow, which leads to the failure of Taylor hypothesis. Secondly, we use one model to investigate the effects of Taylor hypothesis on the solar wind turbulent spectra based on the existence of whistler mode in solar wind turbulence. It is found that the slopes have very small fluctuations in the inertial range; while large variations in the dissipation range. No good correlation exists between the slopes and plasma flow, but the slopes increase with the decease of ?kb (propagation angle with the respect to ambient magnetic field). The broad distribution of the slopes in the dissipation range can used to explain the statistical observations in solar wind, which indicates the possibility of universal spectra in the dissipation range in plasma turbulence. Our results suggest that one should carefully apply the Taylor hypothesis for the turbulence study.

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科学技术处、空间研究院

2014年6月30日