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arXiv 1907.04510astro-ph.SR
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两类太阳局限耀斑

Two Types of Solar Confined Flares

Ting Li, Lijuan Liu, Yijun Hou, Jun Zhang

摘要:

为了解受限耀斑的物理机制,选取了2011-2017年期间的18个受限耀斑,根据其动力学性质和磁位形的不同,将受限耀斑分为两类。“I型”耀斑的特征是滑移重联、强剪切和稳定的暗条。“II型”耀斑几乎没有滑移重联,耀斑后有一个位形。暗条爆发,但被强束缚场限制。“II型”耀斑可用二维MHD模型解释,而“I型”耀斑则需要三维MHD模型。18个耀斑中7个($\sim$ 39 \%)属于“I型”耀斑,11个($\sim$ 61 \%)属于“II型”局限耀斑。“I型”耀斑的耀斑后环具有较强的非势性,而“II型”耀斑的耀斑后环剪切较弱。所有的I型耀斑都表现出平行于极性反转线的带状伸长,速度为几十km/s $^{-1}$。对于“II型”耀斑,只有一小部分显示出沿PIL的带状拉长。我们认为,不同的磁拓扑结构和重联的情况下决定了不同的属性为两种类型的耀斑。多个磁系统之间的滑动磁重联导致“I型”耀斑。对于“II型”耀斑,磁重联发生在爆发暗条下面的反平行磁场中。我们的研究表明,“I型”耀斑占总的大型受限耀斑的三分之一以上,这在进一步的研究中是不应该被忽视的。

英文摘要:

With the aim of understanding the physical mechanisms of confined flares, we selected 18 confined flares during 2011-2017, and classified the confined flares into two types based on their different dynamic properties and magnetic configurations. "Type I" of confined flares are characterized by slipping reconnection, strong shear, and stable filament. "Type II" flares have nearly no slipping reconnection, and have a configuration in potential state after the flare. Filament erupts but is confined by strong strapping field. "Type II" flares could be explained by 2D MHD models while "type I" flares need 3D MHD models. 7 flares of 18 ($\sim$39 \%) belong to "type I" and 11 ($\sim$61 \%) are "type II" confined flares. The post-flare loops (PFLs) of "type I" flares have a stronger non-potentiality, however, the PFLs in "type II" flares are weakly sheared. All the "type I" flares exhibit the ribbon elongations parallel to the polarity inversion line (PIL) at speeds of several tens of km s$^{-1}$. For "type II" flares, only a small proportion shows the ribbon elongations along the PIL. We suggest that different magnetic topologies and reconnection scenarios dictate the distinct properties for the two types of flares. Slipping agnetic reconnections between multiple magnetic systems result in "type I" flares. For "type II" flares, magnetic reconnections occur in anti-parallel magnetic fields underlying the erupting filament. Our study shows that "type I" flares account for more than one third of the overall large confined flares, which should not be neglected in further studies.

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