Coronal mass ejections (CMEs) are complex magnetized plasma structures in which the magnetic field spirals around a central axis, forming what is known as a flux rope (FR). The central FR axis can be oriented at any angle to the ecliptic. Throughout its journey, a CME will encounter interplanetary magnetic field and solar wind which are neither homogeneous nor isotropic. Consequently, CMEs with different orientations will encounter different ambient medium conditions and, thus, the interaction of a CME with its surrounding environment will vary depending on the orientation of its FR axis, among other factors. This study aims to understand the effect of inclination on CME propagation. We performed simulations with the EUHFORIA 3D magnetohydrodynamic model. This study focuses on two CMEs modelled as spheromaks with nearly identical properties, differing only by their inclination. We show the effects of CME orientation on sheath evolution, MHD drag, and non-radial flows by analyzing the model data from a swarm of 81 virtual spacecraft scattered across the inner heliospheric. We have found that the sheath duration increases with radial distance from the Sun and that the rate of increase is greater on the flanks of the CME. Non-radial flows within the studied sheath region appear larger outside the ecliptic plane, indicating a "sliding" of the IMF in the out-of ecliptic plane. We found that the calculated drag parameter does not remain constant with radial distance and that the inclination dependence of the drag parameter can not be resolved with our numerical setup.
Limb Observations of Global Solar Coronal Extreme-ultraviolet Wavefronts: The Inclination, Kinematics, Coupling with the Expanding Coronal Mass Ejections, and Connection with the Coronal Mass Ejection Driven Shocks
Characteristic Scales of Complexity and Coherence within Interplanetary Coronal Mass Ejections: Insights from Spacecraft Swarms in Global Heliospheric Simulations
Assessing VBz variations during CME propagation: a preparatory study for the HENON mission using EUHFORIA
University of Calabria(卡拉布里亚大学);NASA Goddard Space Flight Center(美国国家航空航天局戈达德太空飞行中心);Goddard Planetary Heliophysics Institute, University of Maryland, Baltimore County(马里兰大学巴尔的摩分校戈达德行星日球物理研究所);KU Leuven(荷语鲁汶大学);University of Maria Curie-Skłodowska(玛丽亚·居里-斯克沃多夫斯卡大学);National Institute for Astrophysics(国家天体物理研究所);Space Dynamics Services S.R.L.(空间动力学服务有限公司);Institute of Space Astrophysics and Planetology - INAF(空间天体物理学和行星学研究所(意大利国家天体物理研究所));Università degli Studi di Firenze(佛罗伦萨大学)
Arrival time calculation for interplanetary coronal mass ejections with circular fronts and application to STEREO observations of the 2009 February 13 eruption
Physical Conditions of Coronal Plasma at the transit of a Shock driven by a Coronal Mass Ejection
本文报道了利用白光日冕图像和射电动力学谱确定由日冕物质抛射驱动的冲击波的等离子体物理参数。这里分析的事件是发生在2011年6月7日的壮观爆发,一个快速的CME,随后是色球等离子体柱的喷射,其中一部分落回太阳表面,与M2.5耀斑和II型射电爆发有关。SOHO/LASCO日冕仪(C2和C3)获得的图像被用来跟踪日冕中2-12 R $_\odot$之间的日冕物质抛射驱动的激波,角度间隔约为110 $^\circ$。在这些时间间隔,我们推导出2维(2D)的电子密度,冲击波速度和冲击压缩比的地图,我们测量的冲击倾斜角相对于径向方向。在合理的假设下,这些量被用来推断激波马赫数$M_\text{A}$和激波高度处日冕磁场强度的二维图。我们发现,在早期阶段(2-4 R $_\odot$),整个激波面是超阿尔夫文型的,而在以后(即更高的位置),它只在头部变成超阿尔夫文型的。这与观测到的II型爆发源的位置一致,这是从RDS结合来自WL的冲击运动学和日冕密度推断的。第一次,一个日冕冲击是用来获得一个2D地图的日冕磁场强度超过10 R $_\odot$高度和$\sim 110^\circ$纬度间隔。
Early Evolution of Earth-Directed Coronal Mass Ejections in the Vicinity of Coronal Holes
Hvar Observatory, Faculty of Geodesy, University of Zagreb(萨格勒布大学测地学院哈弗观测台);Institute of Physics, University of Graz(格拉茨大学物理研究所);Department of Physics, University of Helsinki(赫尔辛基大学物理系);Max-Planck-Institut für Sonnensystemforschung(马克斯·普朗克太阳系统研究所)
Validating a Non-conventional Method for Expansion of Coronal Mass Ejections (CMEs) and Investigating the Evolution of a CME Substructures Using Solar Orbiter and Wind Observations
University of Reading(雷丁大学);Austrian Space Weather Office, GeoSphere Austria(奥地利空间天气办公室,地球系统奥地利);Indian Institute of Astrophysics(印度天体物理研究所);Pondicherry University(本地治里大学)
WR 148: Identifying the companion of an extreme runaway massive binary
WR 148(HD 197406)是一个极端失控的系统,被认为是一个短周期(4.3173 d)罕见的WR +致密天体双星的潜在候选者。提供了新的高分辨率,高信噪比的光谱从凯克天文台,我们确定的轨道参数的初级WR和次级,产生各自的预计轨道速度振幅的$88.1\pm3.8$公里的$^{-1}$和$79.2\pm3.1$公里的$^{-1}$和暗示的质量比$1.1\pm0.1$。然后,我们应用移位和添加技术解开的光谱,并获得与WN 7 ha和O 4 -6星兼容的光谱。考虑到从以前的偏振测量观测得出的轨道倾角为$\sim67^\circ$,该系统的总质量将仅为2-3 M $_{\odot}$,这对于一个假定的大质量双星系统来说是前所未有的结果。然而,一个包含37 M $_{\odot}$次级(O 5 V恒星的典型质量)和33 M $_{\odot}$初级(给定质量比)的系统将推断出$\sim18^\circ$的倾角。因此,我们重新考虑以前的方法推导出的轨道倾角的基础上的时间依赖的偏振和测光。虽然偏振结果是不确定的,需要更好的数据,光度结果有利于低倾角。最后,我们计算了WR 148的空间速度,并将失控的轨迹追溯到银河平面(GP)。WR 148的抛射速度为$198\pm27$ km s $^{-1}$,到达当前位置的旅行时间为$4.7\pm0.8$ Myr,因此WR 148很可能是通过年轻星团中…
WD mass and orbital period relation of sdB + He WD binaries
大多数亚矮星B(sdB)+氦白矮星(He WD)双星被认为是由一个特殊的通道形成的。在这个通道中,He WD首先从具有简并核心的红巨星(RG)通过稳定的质量转移产生,而sdB星则从具有简并核心的RG通过共同包络(CE)喷射产生。它们对于CE演化、双星演化和双星群体合成的研究具有重要意义。然而,WD质量和sdB + He WD双星的轨道周期之间的关系还没有专门的研究。在本文中,我们首先使用半解析方法来追踪它们的形成并找到WD质量和轨道周期的关系。然后,我们使用一个详细的恒星演化代码来模拟它们的形成主序星双星。我们发现WD质量和轨道周期之间存在类似的关系,这与观测结果基本一致。对于大多数sdB + He WD系统,如果WD质量(轨道周期)可以确定,则可以利用该关系推断轨道周期(WD质量),然后可以用二元质量函数约束倾角。此外,我们还可以利用这个关系来约束CE喷射效率,并发现相对较大的CE喷射效率是有利的。如果WD和sdB恒星质量都能确定,RG双星的动力学不稳定质量转移的临界质量比也可以被约束。
On the Effect of Large Scale Structures and Turbulence on Solar Eruptive Events: The Cross-Scale Challenge for Space Weather
Istituto Nazionale di Geofisica e Vulcanologia (INGV)(意大利国家地球物理与火山学研究所);Università della Calabria(卡塔尼亚大学);KU Leuven(荷语鲁汶大学);University of Maria Curie-Skłodowska(玛丽亚·居里-斯可多夫斯卡大学)
Comprehensive MHD modelling of ten successive CMEs driving a historic geomagnetic storm -- The 2024 Mothers Day event
University of Iowa(爱荷华大学);University of Michigan(密歇根大学);KU Leuven(荷语鲁汶大学);Indian Institute of Technology Roorkee(印度理工学院鲁尔基分校);University of Maria Curie-Sklodowska(玛丽亚·居里-斯克隆多夫斯卡大学)
Deformation of the CME and CME-driven shock due to interaction with the ambient solar wind: I. Modelling with Cone Model
University of Maryland, Baltimore County(马里兰大学巴尔的摩分校);NASA Goddard Space Flight Center(美国宇航局戈达德太空飞行中心);KU Leuven(荷语鲁汶大学);Royal Observatory of Belgium(比利时皇家天文台)