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arXiv 2303.05074physics.space-phastro-ph.SR
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关于原位太阳风观测中密度涨落标度关系的解释:来自三维湍流模拟的见解

On the Interpretation of the Scalings of Density Fluctuations from In-situ Solar Wind Observations: Insights from 3D Turbulence Simulations

Senbei Du, Hui Li, Zhaoming Gan, Xiangrong Fu

AI总结:

本文利用三维可压缩磁流体动力学模拟,研究了太阳风密度涨落的各向异性效应及采样角度对功率谱和方差的影响,并指出需仔细平均才能从观测中揭示密度变化与湍流马赫数等量的标度关系。

摘要:

太阳风湍流通常被视为弱可压缩的,密度涨落在理论和观测上仍未被充分理解。可压缩磁流体动力学模拟为理解密度涨落的本质提供了有用的见解。我们讨论了与三维湍流模拟和原位观测相关的几个重要效应。由于湍流的各向异性,观测到的量(如功率谱和方差)依赖于采样轨迹与平均磁场之间的夹角。各向异性效应在更小尺度和更低等离子体 beta 下更强。此外,原位测量往往表现出较大范围的变化,即使它们可能来自具有确定平均值的同一总体,因此可能需要仔细的平均处理,以从观测中揭示密度变化与其他湍流量(如湍流马赫数)之间的标度关系。

英文摘要:

Solar wind turbulence is often perceived as weakly compressible and the density fluctuations remain poorly understood both theoretically and observationally. Compressible magnetohydrodynamic simulations provide useful insights into the nature of density fluctuations. We discuss a few important effects related to 3D simulations of turbulence and in-situ observations. The observed quantities such as the power spectrum and variance depend on the angle between the sampling trajectory and the mean magnetic field due to anisotropy of the turbulence. The anisotropy effect is stronger at smaller scales and lower plasma beta. Additionally, in-situ measurements tend to exhibit a broad range of variations, even though they could be drawn from the same population with the defined averages, so a careful averaging may be needed to reveal the scaling relations between density variations and other turbulence quantities such as turbulent Mach number from observations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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