论文标题
剪切引起的连续冠状质量弹出的数值模拟
Numerical simulations of shear-induced consecutive coronal mass ejections
论文作者
论文摘要
方法:隐形CME代表了一类特定的太阳喷发,这些喷发在Coronagraph观察中明确区分了,但它们没有明确的源签名。特定类型的隐形CME发生在先前弹出的后线电流板上,因此,我们使用代码MPI-AMRVAC的2.5D MHD软件包来数值模拟连续的CME,通过将剪切运动施加到内部边界上。初始磁性构型由嵌入双峰太阳风中的三重街机结构组成,并且在南部环系统中发现了剪切的极性反转线。通过适用于当前携带结构的改进方法,不断适应网格。然后,我们比较了所获得的喷发与2009年9月发生的初始多个冠状质量弹出(MCME)事件的观察到的传播方向。我们通过在纬度和总速度的范围绳索中跟踪其通量绳索的中心进一步分析了模拟弹射。还采用了径向上的通量计算,以遵循引入系统中引入的电磁能的演变。 结果:剪切速度中1 \%以内的变化导致第二个CME的三种不同情况,尽管前面的喷发似乎对如此小的变化感到不敏感。因此,根据所应用的剪切速度,我们获得了由施加的剪切驱动的失败的喷发,隐形或CME,作为第二次弹出。将所有喷发的动力学与观察到的MCME事件传播的方向进行了比较,并实现了良好的相关性。 Poynting通量分析揭示了喷发的重要步骤的时间变化。第一次,通过施加的剪切速度变化,在第一次喷发后首次模拟隐形CME。
Methods: Stealth CMEs represent a particular class of solar eruptions that are clearly distinguished in coronagraph observations, but they don't have a clear source signature. A particular type of stealth CMEs occurs in the trailing current sheet of a previous ejection, therefore, we used the 2.5D MHD package of the code MPI-AMRVAC to numerically simulate consecutive CMEs by imposing shearing motions onto the inner boundary. The initial magnetic configuration consists of a triple arcade structure embedded into a bimodal solar wind, and the sheared polarity inversion line is found in the southern loop system. The mesh was continuously adapted through a refinement method that applies to current carrying structures. We then compared the obtained eruptions with the observed directions of propagation of an initial multiple coronal mass ejection (MCME) event that occurred in September 2009. We further analysed the simulated ejections by tracking the centre of their flux ropes in latitude and their total speed. Radial Poynting flux computation was employed as well to follow the evolution of electromagnetic energy introduced into the system. Results: Changes within 1\% in the shearing speed result in three different scenarios for the second CME, although the preceding eruption seems insusceptible to such small variations. Depending on the applied shearing speed, we thus obtain a failed eruption, a stealth, or a CME driven by the imposed shear, as the second ejection. The dynamics of all eruptions are compared with the observed directions of propagation of an MCME event and a good correlation is achieved. The Poynting flux analysis reveals the temporal variation of the important steps of eruptions. For the first time, a stealth CME is simulated in the aftermath of a first eruption, through changes in the applied shearing speed.