Using a classification scheme for solar wind type based on the heliocentric distance of the observation, we look at near perihelion observations from Parker Solar Probe Encounters Four to Fourteen to study the sources of the slow Alfv$é$nic solar wind (SASW). Through Potential Field Source Surface (PFSS) modeling and ballistic mapping, we connect streams to their solar source and find that a primary population of SASW comes from low magnetic field strength regions (low-$B_0$), likely small coronal holes (CHs) and their over-expanded boundaries, while a second population of high field strength (high-$B_0$) seems to emerge from non-CH structures potentially through interchange reconnection with nearby open field lines. This low-$B_0$ SASW shows larger expansion than the fast solar wind (FSW) but similar mass flux, potentially indicating additional heating below the critical point, and emergence from a cooler structure, which could lead to slower wind emerging from CH-like structures. We show that this low-$B_0$ SASW shows stronger preferential acceleration of alpha particles (similar to the FSW) than the high-$B_0$ SASW, and that this is a velocity dependent phenomenon as found in previous studies. To have additional confidence in our mapping results, we quantify the error on both the PFSS model and ballistic mapping and discuss how additional multi-point observations of plasma parameters and composition would allow us to better constrain our models and connect the solar wind to its source.
Effects of Alfvénicity on the Compressible Energy Cascade in Magnetohydrodynamic Solar Wind Turbulence: Evidence from Parker Solar Probe, Solar Orbiter, and WIND observations
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales(布宜诺斯艾利斯大学,理学院);CONICET – Universidad de Buenos Aires, Instituto de Física Interdisciplinaria y Aplicada (INFINA)(阿根廷国家科学研究委员会–布宜诺斯艾利斯大学,交叉与应用物理研究所);Department of Physics, The University of Texas at Austin(德克萨斯大学奥斯汀分校,物理系);Department of Astronomy, University of Maryland, College Park(马里兰大学帕克分校,天文学系);Planetary Magnetospheres Laboratory, NASA Goddard Space Flight Center(NASA戈达德太空飞行中心,行星磁层实验室)
Observations of Transition from Imbalanced to Balanced Kinetic Alfvénic Turbulence
Purple Mountain Observatory, Chinese Academy of Sciences(中国科学院紫金山天文台);Space Sciences Laboratory, University of California, Berkeley(加州大学伯克利分校空间科学实验室);Physics Department, University of California, Berkeley(加州大学伯克利分校物理系);School of Physics and Electronic Sciences, Changsha University of Science and Technology(长沙理工大学物理与电子科学学院);LPC2E, CNRS, CNES, University of Orléans(奥尔良大学CNRS/CNES LPC2E研究中心);International Space Science Institute (ISSI)(国际空间科学研究所);University of California, Berkeley(加州大学伯克利分校)
Characterization of compressible fluctuations in solar wind streams dominated by balanced and imbalanced turbulence: Parker Solar Probe, Solar Orbiter and Wind observations
The University of Texas at Austin(德克萨斯大学奥斯汀分校)
研究通过分析Wind、Solar Orbiter和Parker Solar Probe的数据,探讨太阳风中压缩性波动的尺度依赖性和与等离子体β值及径向距离的关系,揭示压缩性波动在太阳风加速和加热中的作用。
Features of magnetic field switchbacks in relation to the local-field geometry of large-amplitude Alfvénic oscillations: \emph{Wind} and \emph{PSP} observations
Generation and Expansion-Driven Growth of Switchbacks in the Outer Solar Corona and Solar Wind
Imperial College London(帝国理工学院);University of California, Los Angeles(加州大学洛杉矶分校);Auburn University(奥本大学);Space Sciences Laboratory, University of California, Berkeley(加州大学伯克利分校空间科学实验室);Istituto per la Scienza e Tecnologia dei Plasmi (ISTP), Consiglio Nazionale delle Ricerche(等离子体科学与技术研究所,意大利国家研究委员会);The University of Texas at Austin(德克萨斯大学奥斯汀分校)
Coherent events at ion scales in the inner Heliosphere: \textit{Parker Solar Probe} observations during the first Encounter
\textit{Parker Solar Probe}在其第一个近日点嵌入一个高度阿尔夫文慢流时,已经显示出普遍存在的强磁场偏转,即之字形。在这里,我们研究的湍流磁场波动的离子尺度在三个间隔,其特征在于一个不同的之字形活动,确定的行为的磁场径向分量,$B_r$。\textit{Quiet}($B_r$未显示出显著波动)、\textit{weak}($B_r$具有强波动但无反转)和\textit{strong}($B_r$具有完全反转)周期也显示出离子量和Alfvénicity的不同行为。然而,光谱分析表明,每个流的特征在于由典型的Kolmogorov/Kraichnan幂律在惯性范围内,其次是周围的特征离子尺度的休息。该频率范围的特征在于强间歇性活动,存在非压缩相干结构,例如电流片和涡旋状结构,以及被识别为离子回旋模式的波包。虽然,所有这些间歇性事件已被检测到的三个时期,他们有不同的影响,在他们每个人。电流片在\textit{strong}周期中占主导地位,波包在\textit{quiet}间隔中最常见;而在\textit{weak}周期中,观察到涡旋和波包的混合物。这项工作提供了一个深入了解加热问题的碰撞无等离子体,适合在新的太阳能任务的背景下,特别是\textit{Solar Orbiter},这将允许一个准确的磁连通性分析,链接到源区域的不同的间歇性事件的存在。
MMS Insights into CME Driven Sub-Alfvénic Solar Wind at 1 AU
University of Maryland(马里兰大学);NASA Goddard Space Flight Center(NASA戈达德太空飞行中心);University of New Hampshire(新罕布什尔大学);University of Delaware(特拉华大学);University of Colorado Boulder(科罗拉多大学博尔德分校)
Determination of Solar Wind Angular Momentum and Alfvén Radius from Parker Solar Probe Observations
作为太阳的基本参数,阿尔文半径和角动量损失决定了太阳风如何从亚阿尔文转变为超阿尔文,以及太阳如何向下旋转。本文提出了一种基于帕克太阳探测器(PSP)观测资料确定太阳风角动量通量的方法。通过对距太阳0.3 au以内的前四次相遇的平均数据,得到了黄道面附近约为$0.15\times10^{30}$ dyn cm sr $^{-1}$的通量以及粒子与磁场之间0.7:1的通量分配。角动量通量及其粒子分量随太阳风速度的增大而减小,而场中的通量则保持显著的恒定。阿尔文半径的速度依赖性也被观察到,这表明太阳周围有一个“崎岖”的阿尔文表面。根据PSP的轨道设计,只有在相对缓慢的太阳风下,阿尔文表面以下的大量潜水才是合理的。根据在PSP观测到的相同太阳风流的加速度剖面和1天文单位附近的径向对准航天器的加速度剖面,对未探测器进行了评估。我们说明了Réville等人提出的“角动量佯谬”可以通过考虑α粒子的贡献来消除。PSP观测到的大的质子横向速度可能是太阳风加速过程中所固有的,在角动量守恒的情况下,α粒子产生了相反的横向速度。一些恢复的α参数的初步分析往往同意的结果。
Possible Evolution of Minifilament-Eruption-Produced Solar Coronal Jets, Jetlets, and Spicules, into Magnetic-Twist-Wave "Switchbacks" Observed by the Parker Solar Probe (PSP)
Connecting Solar Orbiter remote-sensing observations and Parker Solar Probe in-situ measurements with a numerical MHD reconstruction of the Parker spiral
Alfvénic solar wind intervals observed by Solar Orbiter: Exploiting the capability of the SWA plasma suite and source region investigation
Institute for National Astrophysics (INAF), Institute for Space Astrophysics and Planetology (IAPS)(意大利国家天体物理研究所,空间天体物理学与行星学研究所);University of Michigan(密歇根大学);University of California Los Angeles(加州大学洛杉矶分校);Advanced Heliophysics(高级日球物理学);University College London, Mullard Space Science Laboratory(伦敦大学学院,穆拉德空间科学实验室);Institut de Recherche en Astrophysique et Planétologie, CNRS, Université de Toulouse, CNES(天体物理学与行星学研究所在,法国国家科学研究中心,图卢兹大学,法国国家空间研究中心);Heliophysics Science Division, NASA Goddard Space Flight Center(日球物理学部,NASA戈达德太空飞行中心);ASI - Italian Space Agency(意大利航天局)
Large-scale Structure and Turbulence Transport in the Inner Solar Wind -- Comparison of Parker Solar Probe's First Five Orbits with a Global 3D Reynolds-averaged MHD Model