Three-dimensional propagation of CMEs in a structured solar wind flow: 1. CME launched within the streamer belt
Three-dimensional propagation of CMEs in a structured solar wind flow: 1. CME launched within the streamer belt
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DOI：
10.1029/1998ja900019
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发表时间：
1999
影响因子：
--
通讯作者：
D. Odstrcil;V. Pizzo
中科院分区：
文献类型：
--
作者：
D. Odstrcil;V. Pizzo
利用三维数值流体动力学模型研究了大尺度太阳风结构的时空演化。在太阳附近的内边界处指定了倾斜偶极子外流配置，并通过动力松弛建立了结构化的共转太阳风（SW）流。在内边界处的压力和速度的时间依赖性变化被应用于在流光带内生成瞬态结构。然后研究了0.14 ~ 5.04 Au之间日冕物质抛射（CME）与同转日冕流光带流的动力学相互作用。数值计算结果表明，CME与背景SW的速度和密度结构相互作用，对CME的运动和外观有很大影响，CME的初始形状和密度分布在各个维度上都发生了畸变;它被压缩，CME被困在慢速流光带和高速冕洞流之间，在日冕物质抛射进入前一股高速气流后缘的地方，它会膨胀。因此，一个给定的日冕物质抛射可以在不同的位置观察到显著不同的性质;冲击强度以及冲击波阵面和日冕物质抛射驱动气体之间的距离可以在整个结构中有很大的变化，并且通过扰动的密度分布可以根据位置采取不同的形式。如该模拟所示，CME和共转相互作用区域冲击和热力学结构的合并使单航天器观测的解释变得复杂。
A three‐dimensional (3‐D) numerical hydrodynamic model is used to investigate the temporal and spatial evolution of large‐scale solar wind structures. A tilted‐dipole outflow configuration is specified at the inner boundary near the Sun, and a structured, corotating solar wind (SW) flow is established by dynamic relaxation. Time‐dependent variation of the pressure and velocity at the inner boundary is applied to generate transient structures within the streamer belt. The dynamical interaction of a coronal mass ejection (CME) with the corotating coronal streamer belt flow between 0.14 and 5.04 AU is then investigated. Numerical results show that the motion and appearance of a CME can be strongly affected by its interaction with the velocity and density structure of the background SW. The initial shape and density distribution of the CME is distorted in all dimensions; it is compressed where, the CME is trapped between slow streamer belt and high‐speed coronal hole flows, and it is distended where the CME penetrates into the trailing edge of the preceding high‐speed stream. Thus a given CME can be observed with substantially different properties at different locations; the shock strength as well as the stand‐off distance between the shock front and the CME driver gas can vary considerably across the structure, and the density profile through the disturbance can adopt different forms depending on location. Merging of CME and corotating interaction region shocks and thermodynamic structures as demonstrated in this simulation complicate the interpretation of single‐spacecraft observations.