标题： 由剪切磁拱内电流片反复形成和破裂引起的同源日冕物质抛射 显示英文标题

标题： Homologous Coronal Mass Ejections Caused by Recurring Formation and Disruption of Current Sheet within a Sheared Magnetic Arcade

摘要： 太阳经常从同一源区反复产生具有相似结构的日冕物质抛射，但这些同源爆发是如何被触发的仍然是一个未解之谜。 在这里，通过使用一种新的磁流体力学模拟，我们展示了同源太阳爆发可以通过日冕电流片的反复形成和破坏而被高效地产生，这由单一双极结构中相同极性反转线的持续剪切所驱动。 这些爆发都由相同的机制引发，在该机制中，内部电流片在一个逐渐剪切的双极场中缓慢形成，并且电流片的重联触发并驱动了爆发。 每次爆发并未释放所有的自由能量，而在喷发的磁通绳下方的耀斑后拱桥中保留了大量的能量。 因此，与剪切势场拱桥相比，由于剪切耀斑后拱桥更容易形成新的电流片，这有利于产生下一次爆发。 此外，还发现新的爆发更强，因为新形成的电流片具有更大的电流密度和更低的高度。 此外，我们的结果还表明，对于给定的磁通分布存在一个磁能阈值，一旦接近这个阈值，爆发就会发生。 显示英文摘要

摘要： The Sun often produces coronal mass ejections with similar structure repeatedly from the same source region, and how these homologous eruptions are initiated remains an open question. Here, by using a new magnetohydrodynamic simulation, we show that homologous solar eruptions can be efficiently produced by recurring formation and disruption of coronal current sheet as driven by continuously shearing of the same polarity inversion line within a single bipolar configuration. These eruptions are initiated by the same mechanism, in which an internal current sheet forms slowly in a gradually sheared bipolar field and reconnection of the current sheet triggers and drives the eruption. Each of the eruptions does not release all the free energy but with a large amount left in the post-flare arcade below the erupting flux rope. Thus, a new current sheet can be more easily formed by further shearing of the post-flare arcade than by shearing a potential field arcade, and this is favorable for producing the next eruption. Furthermore, it is found that the new eruption is stronger since the newly formed current sheet has a larger current density and a lower height. In addition, our results also indicate the existence of a magnetic energy threshold for a given flux distribution, and eruption occurs once this threshold is approached.