On the Fourier Contribution of Strong Current Sheets to the High‐Frequency Magnetic Power SpectralDensity of the Solar Wind
On the Fourier Contribution of Strong Current Sheets to the High‐Frequency Magnetic Power SpectralDensity of the Solar Wind
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DOI：
10.1029/2019ja027307
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发表时间：
2020-02
期刊：
影响因子：
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通讯作者：
J. Borovsky;B. Burkholder
中科院分区：
文献类型：
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作者：
J. Borovsky;B. Burkholder
探讨了太阳风高频磁谱功率与太阳风等离子体中强电流片(方向不连续)的空间分布有关的假设。这一假设是基于以前关于电流片和太阳风的磁功率谱的发现：(1)强电流片的幅度分布和等待时间分布决定了频率的“惯性范围”的幅度组成、电子谱带和谱斜率；(2)太阳风中强电流片的厚度决定了结束惯性范围的断点频率。太阳风电流片分别来自WIND 0.09375-S和MMS7.8×10−-3-S磁场数据集，并分别进行傅里叶变换。在太阳风断点以上的频率，(1)电流片的磁功率谱形状与太阳风的磁功率谱形状相似，(2)电流片出现的频率足够频繁，足以解释断点以上太阳风的磁功率。这对太阳风的高频磁功率谱密度的物理基础有影响，补充了对高频谱的能量级联描述。
The hypothesis is explored that the high‐frequency magnetic spectral power of the solar wind is associated with the spatial profiles of strong current sheets (directional discontinuities) in the solar wind plasma. This hypothesis is based on previous findings about current sheets and the solar wind's magnetic power spectra (1) that the amplitude distribution and waiting time distribution of strong current sheets determines the amplituic composition and the electron strade and spectral slope of the “inertial range” of frequencies and (2) that the thicknesses of strong current sheets in the solar wind determine the breakpoint frequency that ends the inertial range. Solar wind current sheets are collected from the WIND 0.09375‐s and MMS 7.8 × 10−3‐s magnetic data sets, and the current sheets are individually Fourier transformed. At frequencies above the solar wind breakpoint (1) the shape of the magnetic power spectra of the current sheets resembles the shape of the magnetic power spectra of the solar wind and (2) the current sheets occur frequently enough to account for the magnetic power of the solar wind above the breakpoint. This has implications for the physics underlying the high‐frequency magnetic power spectral density of the solar wind, supplementing the energy‐cascade description of the high‐frequency spectrum.