Alfvénic versus non-Alfvénic turbulence in the inner heliosphere as observed by Parker Solar Probe
Alfvénic versus non-Alfvénic turbulence in the inner heliosphere as observed by Parker Solar Probe
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帕克太阳探测器观测到的内日球层中的阿尔芬湍流与非阿尔芬湍流
DOI：
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发表时间：
2021
影响因子：
6.5
通讯作者：
the PSP* Team
中科院分区：
文献类型：
--
作者：
M. Velli;C. Shi;O. Panasenco;A. Tenerani;V. R'eville;the PSP* Team
帕克太阳探测器（PSP）在距离太阳前所未有的近距离上测量太阳风的磁场和等离子体参数，为研究太阳风中磁流体动力学（MHD）湍流的早期演变提供了一个很好的机会。本文利用PSP数据探索太阳风湍流的本质，重点关注波动的alfv特征和功率谱及其对日心距离和环境（即大尺度太阳风性质）的依赖，旨在了解源性质、太阳风膨胀和气流相互作用等不同影响在确定湍流状态中的作用。我们对PSP前5个轨道的数据进行了统计调查，重点研究了大MHD尺度上的波动特性随不同太阳风流和太阳距离的变化。本文还对几个选定时期进行了更深入的分析。我们的结果表明，当波动被太阳风向外传播时，磁场谱变陡，而速度谱的形状保持不变。变陡过程受湍流年龄控制，湍流年龄由风速和径向距离共同决定。从统计上看，速度越快的太阳风Alfvé； ity越高，向外传播波分量占主导地位，磁场和动能更加平衡。随着径向距离的增加，向外波的优势逐渐减弱，而当我们靠近太阳时，发现多余的磁能越来越强。我们表明，即使这些流的速度相似，湍流特性也会因流而显著不同，这表明这些流的起源非常不同。特别是，起源于极冕洞附近的慢风的Alfvé；nicity要比起源于活跃区和伪流带的慢风低得多。我们发现，诸如日球层电流片和气流速度切变等结构在改变湍流性质方面起着重要作用。</p><p>* PSP团队： ；斯图尔特·d·贝尔， ；贾斯汀·卡斯珀，凯利·科瑞克，j·w·邦内尔，蒂埃里·杜多克·德威特，基思·格茨，彼得·r·哈维，罗伯特·j·麦克道尔，大卫·马拉斯皮纳，马克·普卢帕，安东尼·w·凯斯，戴维·拉尔森， ；珍妮·维尼罗，罗伯托·利维，迈克尔·史蒂文斯，菲利斯·惠特尔西，米兰·马克西莫维奇和米歇尔·蒙库奎</p>
<p>Parker Solar Probe (PSP) measures the magnetic field and plasma parameters of the solar wind at unprecedentedly close distances to the Sun, providing a great opportunity to study the early-stage evolution of magnetohydrodynamic (MHD) turbulence in the solar wind. Here we use PSP data to explore the nature of solar wind turbulence focusing on the Alfvénic character and power spectra of the fluctuations and their dependence on heliocentric distance and context (i.e., large-scale solar wind properties), aiming to understand the role that different effects such as source properties, solar wind expansion, and stream interaction might play in determining the turbulent state. We carried out a statistical survey of the data from the first five orbits of PSP with a focus on how the fluctuation properties at the large MHD scales vary with different solar wind streams and the distance from the Sun. A more in-depth analysis from several selected periods is also presented. Our results show that as fluctuations are transported outward by the solar wind, the magnetic field spectrum steepens while the shape of the velocity spectrum remains unchanged. The steepening process is controlled by the age of the turbulence, which is determined by the wind speed together with the radial distance. Statistically, faster solar wind has higher Alfvénicity with a more dominant outward propagating wave component and more balanced magnetic and kinetic energies. The outward wave dominance gradually weakens with radial distance, while the excess of magnetic energy is found to be stronger as we move closer toward the Sun. We show that the turbulence properties can significantly vary from stream to stream even if these streams are of a similar speed, indicating very different origins of these streams. Especially, the slow wind that originates near the polar coronal holes has much lower Alfvénicity compared with the slow wind that originates from the active regions and pseudostreamers. We show that structures such as the heliospheric current sheet and wind stream velocity shears can play an important role in modifying the properties of the turbulence.</p><p>*The PSP Team: Stuart D.Bale,  Justin Kasper, Kelly Korreck, J. W. Bonnell, Thierry Dudok de Wit, Keith Goetz, Peter R. Harvey, Robert J. MacDowall, David Malaspina, Marc Pulupa, Anthony W.Case, Davin Larson,  Jenny Verniero, Roberto Livi, Michael Stevens, PhyllisWhittlesey, Milan Maksimovic, and Michel Moncuquet</p>
影响因子：
64.8
作者：
Kasper, J. C.;Bale, S. D.;Schwadron, N. A.
通讯作者：
Schwadron, N. A.
阿尔文波动力学对太阳风大尺度特性的作用：MHD 模拟与帕克太阳探测器 E1 数据的比较
DOI：
10.3847/1538-4365/ab4fef
发表时间：
2020
期刊：
The Astrophysical Journal Supplement Series
影响因子：
--
作者：
Réville, Victor;Velli, Marco;Panasenco, Olga;Tenerani, Anna;Shi, Chen;Badman, Samuel T.;Bale, Stuart D.;Kasper, J. C.;Stevens, Michael L.;Korreck, Kelly E.
通讯作者：
Korreck, Kelly E.
影响因子：
8.7
作者：
Chen, C. H. K.;Bale, S. D.;Whittlesey, P.
通讯作者：
Whittlesey, P.