Department of Mathematical Sciences, Durham University, Durham DH1 3LE, UK.
Heliophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA.
Nature. 2017 Apr 26;544(7651):452-455. doi: 10.1038/nature22050.
Magnetically driven eruptions on the Sun, from stellar-scale coronal mass ejections to small-scale coronal X-ray and extreme-ultraviolet jets, have frequently been observed to involve the ejection of the highly stressed magnetic flux of a filament. Theoretically, these two phenomena have been thought to arise through very different mechanisms: coronal mass ejections from an ideal (non-dissipative) process, whereby the energy release does not require a change in the magnetic topology, as in the kink or torus instability; and coronal jets from a resistive process involving magnetic reconnection. However, it was recently concluded from new observations that all coronal jets are driven by filament ejection, just like large mass ejections. This suggests that the two phenomena have physically identical origin and hence that a single mechanism may be responsible, that is, either mass ejections arise from reconnection, or jets arise from an ideal instability. Here we report simulations of a coronal jet driven by filament ejection, whereby a region of highly sheared magnetic field near the solar surface becomes unstable and erupts. The results show that magnetic reconnection causes the energy release via 'magnetic breakout'-a positive-feedback mechanism between filament ejection and reconnection. We conclude that if coronal mass ejections and jets are indeed of physically identical origin (although on different spatial scales) then magnetic reconnection (rather than an ideal process) must also underlie mass ejections, and that magnetic breakout is a universal model for solar eruptions.
太阳上的磁驱动爆发,从小尺度日冕 X 射线和极紫外喷流到恒星尺度日冕物质抛射,经常观察到涉及丝状高应力磁通量的抛射。从理论上讲,这两种现象被认为是通过非常不同的机制产生的:日冕物质抛射是一种理想(非耗散)过程,其中能量释放不需要改变磁拓扑结构,例如扭结或环体不稳定性;日冕喷流则是由涉及磁重联的电阻过程产生的。然而,最近的新观测结果得出结论,所有日冕喷流都是由丝状物质抛射驱动的,就像大质量抛射一样。这表明这两种现象具有相同的物理起源,因此可能存在单一的机制,即质量抛射是由磁重联引起的,或者喷流是由理想不稳定性引起的。在这里,我们报告了一种由丝状物质抛射驱动的日冕喷流的模拟,其中太阳表面附近一个高度剪切的磁场区域变得不稳定并爆发。结果表明,磁重联通过“磁爆发”-丝状物质抛射和重联之间的正反馈机制导致能量释放。我们的结论是,如果日冕物质抛射和喷流确实具有相同的物理起源(尽管在不同的空间尺度上),那么磁重联(而不是理想过程)也必须是质量抛射的基础,并且磁爆发是太阳爆发的通用模型。