Multispacecraft Study of the Interaction Between an Interplanetary Shock and a Solar Wind Flux Rope
Multispacecraft Study of the Interaction Between an Interplanetary Shock and a Solar Wind Flux Rope
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DOI：
10.1029/2019ja026748
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发表时间：
2019-12
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影响因子：
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通讯作者：
X. Blanco‐Cano;D. Burgess;T. Sundberg;P. Kajdič
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文献类型：
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作者：
X. Blanco‐Cano;D. Burgess;T. Sundberg;P. Kajdič
行星际（IP）冲击是由快速日冕喷射物在日光层中驱动的，它们可以加速粒子，并与太阳高能粒子和高能风暴粒子事件有关。 IP 冲击可以与太阳风和磁层中的结构相互作用。我们展示了当 IP 激波与小规模磁通绳状结构 (FRLS) 相互作用时，其特性如何变化。来自 Cluster、Wind 和 ACE 的数据表明，航天器观察到了不同演化阶段的激波与 FRLS 相互作用。 Wind 和 ACE 观察激波交叉处的 FRLS； Cluster 观察了 FRLS 穿过激波后的下游情况。激波-FRLS相互作用改变激波几何形状，影响离子注入过程、高能粒子通量和上游/下游区域。 Wind 和 ACE 观察到准垂直激波，而 Cluster 则跨越了准平行激波和具有多种离子分布的前震。 FRLS 在至少 ∼ 10-20 RE 的范围内修改了冲击。 Cluster 测量的离子前震的复杂性可以通过冲击从准垂直过渡到准平行的动力学以及磁通绳内磁场的几何形状来解释。能量高达 125 keV 的粒子通量受到 FRLS 激波相互作用的影响，调节相关的高能风暴粒子事件。在使用多航天器观测之前，尚未讨论过 FRLS 与 IP 冲击的相互作用。像这样的相互作用应该经常发生在激波前沿；因此，它们对于更好地理解激波结构、演化和粒子加速非常重要。
Interplanetary (IP) shocks are driven in the heliosphere by fast coronal ejecta, they can accelerate particles and are associated with solar energetic particle and energetic storm particle events. IP shocks can interact with structures in the solar wind and with magnetospheres. We show how the properties of an IP shock change when it interacts with a small‐scale flux rope‐like structure (FRLS). Data from Cluster, Wind, and ACE show that the spacecraft observed the shock‐FRLS interaction at different stages of evolution. Wind and ACE observed the FRLS at shock crossing; Cluster observed the FRLS downstream, after it had crossed the shock. The shock‐FRLS interaction changes shock geometry, affecting ion injection processes, energetic particles fluxes, and the upstream/downstream regions. While Wind and ACE observed a quasi‐perpendicular shock, Cluster crossed a quasi‐parallel shock and a foreshock with a variety of ion distributions. The FRLS modified the shock on scales of at least ∼ 10–20 RE. The complexity of the ion foreshock measured by Cluster is explained by the dynamics of the shock transitioning from quasi‐perpendicular to quasi‐parallel and the geometry of the magnetic field within the flux rope. Fluxes of particles with energy up to 125 keV are affected by the FRLS‐shock interaction, modulating the associated energetic storm particle event. The interaction of a FRLS with an IP shock has not been discussed before using multispacecraft observations. Interactions like this should occur often along the shock fronts; hence, they are important for a better understanding of shock structure, evolution, and particle acceleration.