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arXiv 2201.04864physics.space-phphysics.data-anphysics.plasm-ph
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亚质子尺度下太阳风的马尔可夫特征

Markovian Features of the Solar Wind at Sub-Proton Scales

Simone Benella, Mirko Stumpo, Giuseppe Consolini, Tommaso Alberti, Vincenzo Carbone, Monica Laurenza

摘要:

由太阳风从太阳带出的行星际磁场显示出大范围尺度的波动。虽然在大尺度上,比如在低于0.1-1 Hz的频率下,波动显示出具有良好定义的Kolmogorov惯性范围的充分发展的湍流的明确的普遍特征,但小尺度制度的物理和动力学性质以及它们与大尺度制度的联系仍然是一个有争议的话题。在这项工作中,我们研究了近太阳磁场波动在亚质子尺度上通过分析的马尔可夫性质的波动和恢复的基本信息的性质的能量转移在不同的尺度。通过评估的Kramers-Moyal系数,我们发现,在亚质子范围内的波动被很好地描述为一个马尔可夫过程的概率密度函数(PDF)通过福克-普朗克(FP)方程建模。此外,我们表明,PDF的形状是全球尺度不变的,类似的FP方程在不同尺度上的固定解恢复。我们的亚质子尺度波动的马尔可夫性质的结果的相关性也讨论了在这一领域的湍流的发生。

英文摘要:

The interplanetary magnetic field carried out from the Sun by the solar wind displays fluctuations on a wide range of scales. While at large scales, say at frequencies lower than 0.1-1 Hz, fluctuations display clear universal characteristics of fully developed turbulence with a well defined Kolmogorov's like inertial range, the physical and dynamical properties of the small-scale regime as well as their connection with the large-scale ones are still a debated topic. In this work we investigate the near-Sun magnetic field fluctuations at sub-proton scales by analyzing the Markov property of fluctuations and recovering basic information about the nature of the energy transfer across different scales. By evaluating the Kramers-Moyal coefficients we find that fluctuations in the sub-proton range are well described as a Markovian process with Probability Density Functions (PDFs) modeled via a Fokker-Planck (FP) equation. Furthermore, we show that the shape of the PDFs is globally scale-invariant and similar to the one recovered for the stationary solution of the FP equation at different scales. The relevance of our results on the Markovian character of sub-proton scale fluctuations is also discussed in connection with the occurrence of turbulence in this domain.

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