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arXiv 1801.03136astro-ph.SR
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ICME-ICME相互作用的数值模拟

Numerical simulations of ICME-ICME interactions

Tatiana Niembro, Alejandro Lara, Ricardo F. González, J. Cantó

摘要:

本文对行星际介质中相互作用的日冕物质抛射进行了流体动力学模拟。在这些事件中,两个连续的日冕物质抛射在几个小时的时间间隔内从太阳以相似的方向发射。在我们的数值模型中,我们假设周围的太阳风的特点是它的速度和质量损失率。然后,当流速和质量损失率相对于环境太阳风条件在两个时间间隔内突然改变时,CME产生,这对应于CME的持续时间。在它们相互作用之后,形成合并区域,并作为单一结构演化成行星际介质。在这项工作中,我们感兴趣的是这个合并区域的一般形态,这取决于环境太阳风和每个CME的初始参数。为了理解这种形态,我们进行了参数研究,其中我们的特点的影响,初始参数的变化上的密度和速度分布在1 AU,作为参考,有据可查的事件2004年7月25日。基于这种参数化,我们能够以高精度再现所观察到的轮廓。然后,我们将参数化结果应用于2010年5月23日,2010年8月1日和2012年11月9日的相互作用事件。通过这种方法,并使用CME观测误差内的输入参数值,我们的模拟剖面再现了在1 AU观测到的主要特征。尽管我们没有考虑到磁场,我们的模型提供了一个物理洞察ICME的传播和相互作用。

英文摘要:

We present hydrodynamical simulations of interacting Coronal Mass Ejections in the Interplanetary medium (ICMEs). In these events, two consecutive CMEs are launched from the Sun in similar directions within an interval of time of a few hours. In our numerical model, we assume that the ambient solar wind is characterized by its velocity and mass-loss rate. Then, the CMEs are generated when the flow velocity and mass-loss rate suddenly change, with respect to the ambient solar wind conditions during two intervals of time, which correspond to the durations of the CMEs. After their interaction, a merged region is formed and evolve as a single structure into the interplanetary medium. In this work, we are interested in the general morphology of this merged region, which depends on the initial parameters of the ambient solar wind and each of the CMEs involved. In order to understand this morphology, we have performed a parametric study in which we characterize the effects of the initial parameters variations on the density and velocity profiles at 1 AU, using as reference the well-documented event of July 25th, 2004. Based on this parametrization we were able to reproduce with a high accuracy the observed profiles. Then, we apply the parametrization results to the interaction events of May 23, 2010; August 1, 2010; and November 9, 2012. With this approach and using values for the input parameters within the CME observational errors, our simulated profiles reproduce the main features observed at 1 AU. Even though we do not take into account the magnetic field, our models give a physical insight into the propagation and interaction of ICMEs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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