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arXiv 2404.03075astro-ph.SRphysics.plasm-phphysics.space-ph
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内日球层中磁湍流功率谱对折返结构存在与否的独立性

The Independence of Magnetic Turbulent Power Spectra to the Presence of Switchbacks in the Inner Heliosphere

Peter Tatum, David Malaspina, Alexandros Chasapis, Benjamin Short

AI总结:

本文利用帕克太阳探针数据研究折返结构对太阳风磁湍流功率谱的影响,发现折返结构偏转角不会显著增加惯性区或动力学尺度的波动功率,表明其与湍流级联耦合较弱,对太阳风加热贡献有限。

摘要:

我们关于太阳风知识中一个突出的空白是折返结构与太阳风湍流之间的关系。折返结构是嵌入在太阳风流中的背景磁场的大幅涨落,甚至是反转。已有研究提出,折返结构可能作为湍流的产物而形成,并通过与湍流级联的耦合而衰减。在这项工作中,我们考察太阳风磁场湍流的性质在存在或不存在折返结构时如何变化。具体而言,我们利用帕克太阳探针的原位粒子和磁场测量数据,分别测量惯性区和动力学区的磁场湍流波动功率,并将其作为折返结构磁偏转角的函数。我们证明,在航天器参考系中背景磁场与太阳风速度之间的夹角($θ_{vB}$)强烈决定了帕克太阳探针采样的是平行于还是垂直于背景磁场的波动功率。此外,我们表明$θ_{vB}$受到折返结构磁偏转角的强烈调制。在这项分析中,我们证明折返结构偏转角并不对应于惯性区或动力学尺度上波动功率的任何显著增加。这一结果意味着折返结构不会通过湍流波粒相互作用与惯性区或动力学区的湍流级联发生强烈耦合。因此,我们不期望折返结构通过这种类型的能量转换途径对太阳风加热产生显著贡献,尽管通过其他机制(如磁重联)的贡献可能仍然显著。

英文摘要:

An outstanding gap in our knowledge of the solar wind is the relationship between switchbacks and solar wind turbulence. Switchbacks are large fluctuations, even reversals, of the background magnetic field embedded in the solar wind flow. It has been proposed that switchbacks may form as a product of turbulence and decay via coupling with the turbulent cascade. In this work, we examine how properties of solar wind magnetic field turbulence vary in the presence or absence of switchbacks. Specifically, we use in-situ particle and fields measurements from Parker Solar Probe to measure magnetic field turbulent wave power, separately in the inertial and kinetic ranges, as a function of switchback magnetic deflection angle. We demonstrate that the angle between the background magnetic field and the solar wind velocity in the spacecraft frame ($θ_{vB}$) strongly determines whether Parker Solar Probe samples wave power parallel or perpendicular to the background magnetic field. Further, we show that $θ_{vB}$ is strongly modulated by the switchback magnetic deflection angle. In this analysis, we demonstrate that switchback deflection angle does not correspond to any significant increase in wave power in either the inertial range or at kinetic scales. This result implies that switchbacks do not strongly couple to the turbulent cascade in the inertial or kinetic ranges via turbulent wave-particle interactions. Therefore, we do not expect switchbacks to contribute significantly to solar wind heating through this type of energy conversion pathway, although contributions via other mechanisms, such as magnetic reconnection may still be significant.

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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