Confined and Ejective Eruptions of Kink-unstable Flux Ropes
Confined and Ejective Eruptions of Kink-unstable Flux Ropes
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DOI：
10.1086/462412
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发表时间：
2005-07
期刊：
影响因子：
--
通讯作者：
T. Török;B. Kliem
中科院分区：
文献类型：
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作者：
T. Török;B. Kliem
作为太阳爆发的模型，研究了锚定在光球层中的无力日冕磁通绳的理想螺旋扭折不稳定性。用Titov和Démoulin的磁绳模型作为MHD模拟的初始条件，螺旋形状的发展和受限（或失败）的灯丝喷发（2002年5月27日）的上升轮廓都与观测结果非常一致。通过修改模型，使磁场下降更迅速地与高度以上的磁通绳，一个完整的（或喷射）的绳喷发得到非常好的协议与发展的螺旋形状和指数到线性的上升轮廓的快速日冕物质抛射（CME）在2001年5月15日。这证实了扭曲磁通绳的螺旋扭折不稳定性可能是太阳爆发的启动机制和最初的驱动力。模拟结果与许多喷发的特性一致，表明它们通常是由扭结不稳定性触发的。上覆场随高度的减小是决定不稳定性是否导致局限事件或CME的主要因素。
The ideal helical kink instability of a force-free coronal magnetic flux rope, anchored in the photosphere, is studied as a model for solar eruptions. Using the flux rope model of Titov and Démoulin as the initial condition in MHD simulations, both the development of helical shape and the rise profile of a confined (or failed) filament eruption (on 2002 May 27) are reproduced in very good agreement with the observations. By modifying the model such that the magnetic field decreases more rapidly with height above the flux rope, a full (or ejective) eruption of the rope is obtained in very good agreement with the developing helical shape and the exponential-to-linear rise profile of a fast coronal mass ejection (CME) on 2001 May 15. This confirms that the helical kink instability of a twisted magnetic flux rope can be the mechanism of the initiation and the initial driver of solar eruptions. The agreement of the simulations with properties that are characteristic of many eruptions suggests that they are often triggered by the kink instability. The decrease of the overlying field with height is a main factor in deciding whether the instability leads to a confined event or to a CME.