Up to present, the largest data set of SEP events in the inner heliosphere are the observations by the two Helios spacecraft. We re-visit a sample of 15 solar relativistic electron events measured by the Helios mission with the goal of better characterising the injection histories of solar energetic particles and their interplanetary transport conditions at heliocentric distances <1 AU. The measurements provided by the E6 instrument on board Helios provide us with the electron directional distributions in eight different sectors that we use to infer the detailed evolution of the electron pitch-angle distributions. The results of a Monte Carlo interplanetary transport model, combined with a full inversion procedure, were used to fit the observed directional intensities in the 300-800 keV nominal energy channel. Unlike previous studies, we have considered both the energy and angular responses of the detector. This method allowed us to infer the electron release time profile at the source and determine the electron interplanetary transport conditions. We discuss the duration of the release time profiles and the values of the radial mean free path, and compare them with the values reported previously in the literature using earlier approaches. Five of the events show short injection histories (<30 min) at the Sun and ten events show long-lasting (>30 min) injections. The values of mean free path range from 0.02 AU to 0.27 AU. The inferred injection histories match with the radio and soft x-ray emissions found in literature. We find no dependence of the radial mean free path on the radial distance. In addition, we find no apparent relation between the strength of interplanetary scattering and the size of the solar particle release.
Characteristic Scales of Complexity and Coherence within Interplanetary Coronal Mass Ejections: Insights from Spacecraft Swarms in Global Heliospheric Simulations
Evolving Solar Wind Flow Properties of Magnetic Inversions Observed by Helios
帕克太阳探测器(英语:Parker Solar Probe)(PSP)在其第一次与太阳距离接近r = 0.16天文单位时,观测到日光层磁场(英语:Heliospheric magnetic field)(HMF)中的许多局部反转或反转,伴随着太阳风速度的大幅尖峰。太阳能和原位机制已被建议解释HMF反转的存在一般。先前使用太阳神1号的工作,覆盖0.3-1AU,观察到逆HMF随着r的增加而变得更加常见,这表明一些日光层驱动过程产生或放大了反转。这项研究扩展了这些发现,通过分析反转相关的变化,在等离子体属性相同的大数据集,促进观察'strahl'电子,以确定未扰动的磁极性。我们发现,许多反演表现出反相关的场和速度扰动,因此特征Alfvénic,但许多也强烈偏离这种关系在一个明显的连续属性。随着r的增加,反演进一步偏离“理想的”阿尔夫维尼克情况,因为更多的能量被分配在场中,而不是等离子体中,扰动的分量。这种偏离对于具有较大密度和磁场强度变化的反转以及缓慢的太阳风特性的反转是最大的。我们没有发现任何证据表明,偏离“理想”Alfvénicity的反演有不同的生成过程,从那些更Alfvénic。相反,不同的反转特性可以基于不同太阳风流中的传输或形成而被印记。
Tracking a beam of electrons from the low solar corona into interplanetary space with the Low Frequency Array, Parker Solar Probe and 1 au spacecraft
III型射电暴是温和相对论性电子束从低日冕传播到日光层的等离子体发射的结果,如果它们与日光层航天器的位置对齐,最终可以在原地检测到。在这里,我们观察到一个III型射电爆发从0.1-16兆赫使用帕克太阳探测器(PSP)领域的射频频谱仪(RFS),并从20-80兆赫使用低频阵列(LOFAR)。该事件与任何可检测到的耀斑活动无关,但属于PSP遭遇2期间发生的持续III型噪声风暴的一部分。LOFAR射电源向三维空间的反投影表明,III型射电爆发源位于1.6-3 R $_\odot$的开放磁场上,起源于东经48 $^o$附近的近赤道活动区。结合PSP/RFS观测与风/波和立体声/波,我们重建的第三类射电源轨迹在日光层内部PSP的位置,假设黄道约束。随后在STEREO-A航天器上在兼容的时间原位检测到高能电子增强,尽管开始和持续时间表明单独的爆发有助于增强的一个子集。这项工作表明,日冕中相对小规模的通量出现可以导致电子束从低日冕注入日光层,而不需要强烈的太阳耀斑。这项研究还明确强调了地面和天基无线电观测相结合的互补性,特别是在PSP时代。
The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Optimization of the Spectral Line Inversion Code
斯托克斯矢量的快速反演(VFISV)是一个Milne-Eddington谱线反演程序,用于通过太阳动力学天文台(SDO)上的日震和磁成像仪(HMI)对6173 A Fe I谱线上的斯托克斯矢量的观测来确定太阳光球层的磁性和热力学参数。我们报告了对原始VFISV反演代码的修改,以优化其在HMI数据管道中的操作,并在活动区域提供最平滑的解决方案。这些变化要么加快了计算速度,要么降低了算法无法收敛到满意解的频率。此外,这里报告了在原始VFISV版本中检测到并修复的编码错误。
The Polarimetric and Helioseismic Imager for Solar Orbiter: SO/PHI
{ \em Solar Orbiter}是欧洲航天局(ESA)与美国宇航局(NASA)合作的下一个太阳物理任务,计划于2018年发射。该航天器设计为在高度偏心轨道的近日点接近太阳0.28AU。与太阳的接近也将使其在极紫外和可见波长下以均匀的高分辨率进行观测。这样的观测对于了解更多关于太阳大气的磁耦合是至关重要的。在飞行任务的后期阶段,航天器将离开黄道,从太阳纬度高达33 $^\circ$的地方研究神秘的太阳两极。
A data-driven physics-based transport model of solar energetic particles accelerated by coronal mass ejection shocks propagating through the solar coronal and heliospheric magnetic fields
Tracking a solar energetic eruption and associated energetic particles from Sun to spacecraft
University of Turku(图尔库大学);Turku Collegium for Science, Medicine and Technology, University of Turku(图尔库科学与技术医学学院,图尔库大学);University of Graz(格拉茨大学);Leibniz Institute for Astrophysics Potsdam (AIP)(波茨坦莱布尼茨天体物理研究所 (AIP));LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université, CNRS(拉格朗日天体物理学实验室,巴黎天文台,巴黎文理研究大学,索邦大学,巴黎西岱大学,塞吉-蓬图瓦兹大学,法国国家科学研究中心)
Solar Energetic Proton Events Observed by the High Energy Telescopes on the STEREO Spacecraft or at the Earth During the First Solar Orbit of STEREO A (2006 to 2023)
University of Maryland(马里兰大学);NASA Goddard Space Flight Center(美国宇航局戈达德太空飞行中心)
A study of solar energetic particle transport on 30 March 2022 using multi-spacecraft data assimilation
Japan Agency for Marine-Earth Science and Technology(日本海洋地球科学技术局);Nagoya University(名古屋大学);Kyung Hee University(庆熙大学);Japan Aerospace Exploration Agency(日本宇宙航空研究开发机构);European Space Agency(欧洲空间局);Austrian Academy of Sciences(奥地利科学院);Kyoto University(京都大学)