A Spectroscopic Observation of a Magnetic Reconnection Site in a Small Flaring Event
A Spectroscopic Observation of a Magnetic Reconnection Site in a Small Flaring Event
复制标题
DOI：
10.1086/505638
复制
发表时间：
2006-09
期刊：
影响因子：
--
通讯作者：
H. Hara;Y. Nishino;K. Ichimoto;J. Delaboudiniere
中科院分区：
文献类型：
--
作者：
H. Hara;Y. Nishino;K. Ichimoto;J. Delaboudiniere
通过在Norikura太阳天文台利用地面日冕仪对6374 μ m处的Fe X射线发射线的分光观测，在一次小能量释放的耀斑中观测到两种日冕双向流。我们发现在耀斑环顶部有一个±3 km s-1的双向流动。在流动中没有观察到谱线强度和谱线宽度的显著增加。从耀斑环的几何形状和Fe X多普勒速度的符号，我们得出结论，双向流动是重联流入耀斑环上方。我们估计该事件的重新连接率约为0.003。另一种是沿耀斑后环沿着的双向流动，线强度和多普勒速度显著增加。这种流动被解释为一个冷却上升流的速度约为10公里s-1沿着一个postflare环路从其下部。我们还发现，在环顶区的非热线宽的增加开始时，线强度达到峰值。这支持存在一种机制，以增强湍流等离子体运动中的环顶区域。
We have observed two types of coronal bidirectional flows in a flare with a small energy release through a spectroscopic observation of the Fe X emission line at 6374 Å with a ground-based coronagraph at the Norikura Solar Observatory. We find a bidirectional flow of ±3 km s-1 above the top of a flare loop. Remarkable increases of the line intensity and line width are not observed in the flow. From the loop geometry and sign of the Fe X Doppler velocity we conclude that the bidirectional flow is reconnection inflow above the flare loop. We estimate the reconnection rate to be ~0.003 for this event. The other bidirectional flow is observed along postflare loops with significant increases of the line intensity and Doppler velocity. This flow is interpreted as a cooling upflow having a velocity of ~10 km s-1 along a postflare loop from its lower part. We also find that the increase of the nonthermal line width in the loop-top region starts when the line intensity reaches its peak. This supports the presence of a mechanism to enhance turbulent plasma motions in the loop-top region.