Abstract—

Cosmic plasma represents a natural laboratory for studying turbulence in a wide range of scales. Rapid measurements of the ion flux by the Bright Monitor of the Solar Wind (BMSW) instrument on the Spektr-R satellite make it possible to investigate the characteristics of the plasma turbulence in the solar wind and the magnetosheath at ion and sub-ion scales. This study analyzes the question, in what manner do turbulent cascade characteristics, at these scales in the magnetosheath, depend on the characteristics of the solar wind’s plasma turbulence in front of Earth’s bow shock (BS). Several crosses of Earth’s BS by the Spektr-R satellite are analyzed. A comparison of the shapes of the spectra of ion flux fluctuations and exponents of power-law functions, which describe the spectra at kinetic and magnetohydrodynamic scales in front of and behind Earth’s BS is carried out. It is shown that, directly behind Earth’s BS on magnetohydrodynamic scales, the spectra deviate from the form predicted by the developed turbulence theories and observed in the solar wind. This feature of the spectra indicates the redistribution of energy in the turbulent cascade immediately behind the near-Earth shock wave. At kinetic scales, steeper spectra are usually observed behind the near-Earth shock wave front than in the solar wind, but their slope is determined by the properties of the turbulent cascade in the incident flow. It is shown that the strongest difference between turbulence characteristics in front of and behind Earth’s BS is observed during solar wind flow periods associated with the regions of compression before interplanetary manifestations of coronal mass ejections.

中文翻译：

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受太阳风等离子体湍流影响的磁石场湍流

摘要-

宇宙等离子体代表了一个天然的实验室，用于研究各种规模的湍流。通过Spektr-R卫星上的太阳风明亮监测器（BMSW）仪器对离子通量进行快速测量，有可能研究离子和亚离子尺度下太阳风中的等离子湍流以及磁石场的特征。这项研究分析了这样一个问题：在磁石表面的这些尺度上，湍流级联特性以何种方式取决于地球弓激波（BS）前方太阳风的等离子湍流的特性。Spektr-R对地球的BS的几次穿越卫星进行了分析。进行了离子通量涨落和幂律函数指数的光谱形状比较，这些光谱描述了地球BS前后的动力学和磁流体动力学尺度的光谱。结果表明，在磁流体动力学尺度上，地球的BS紧随其后，光谱偏离了已发展的湍流理论所预测并在太阳风中观测到的形式。频谱的这一特征表明，在近地冲击波后面的湍流叶栅中能量重新分布。在动力学尺度上，通常在近地激波波前比在太阳风中观察到更陡峭的光谱，但是它们的斜率由入射流中湍流叶栅的特性决定。