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arXiv 1307.7201astro-ph.SR
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交感日冕亮点的色球蒸发

Chromospheric evaporation in sympathetic coronal bright points

Q. M. Zhang, H. S. Ji

摘要:

色球蒸发是太阳耀斑中的一个重要过程,人们利用光谱观测对色球蒸发进行了广泛的研究。然而,直接软X射线(SXR)成像的过程是罕见的,特别是在远程增亮与最近引起了极大的关注的主要耀斑。{We试图找到色球蒸发的证据,并找出交感日冕亮点(CBP)过程的原因,即,由主CBP引起的远程增亮。{We利用2009年8月23日在日之出航天器上的X射线望远镜(XRT)对CBPs进行的高节奏和高分辨率SXR观测。{We发现从主CBP传播的热传导前沿,即,BP1,到交感神经CBP之一,即,BP 2与BP 1相距60 $\arcsec$。热传导的视速度为$\sim$ 138 km s $^{-1}$。之后,热等离子体以$\sim$ 76 km s $^{-1}$的速度向上流入连接BP1和BP2的环,这是色球蒸发的明显特征。在连接BP 1和另一交感神经CBP的环路中也观察到类似的上行流,即,BP3与BP1相差80 $\arcsec$,但不如BP2显著。上升流的视速度为$\sim$ 47 km s $^{-1}$。从BP1到BP3的热传导前沿传播没有被很好地识别,除了同样源自BP1的射流状运动。{We提出交感CBP中的温和色球蒸发是由源自初级CBP的热传导引起的。

英文摘要:

{Chromospheric evaporation is a key process in solar flares that has extensively been investigated using the spectroscopic observations. However, direct soft X-ray (SXR) imaging of the process is rare, especially in remote brightenings associated with the primary flares that have recently attracted dramatic attention.} {We intend to find the evidence for chromospheric evaporation and figure out the cause of the process in sympathetic coronal bright points (CBPs), i.e., remote brightenings induced by the primary CBP.} {We utilise the high-cadence and high-resolution SXR observations of CBPs from the X-ray Telescope (XRT) aboard the Hinode spacecraft on 2009 August 23.} {We discover thermal conduction front propagating from the primary CBP, i.e., BP1, to one of the sympathetic CBPs, i.e., BP2 that is 60$\arcsec$ away from BP1. The apparent velocity of the thermal conduction is $\sim$138 km s$^{-1}$. Afterwards, hot plasma flowed upwards into the loop connecting BP1 and BP2 at a speed of $\sim$76 km s$^{-1}$, a clear signature of chromospheric evaporation. Similar upflow was also observed in the loop connecting BP1 and the other sympathetic CBP, i.e., BP3 that is 80$\arcsec$ away from BP1, though less significant than BP2. The apparent velocity of the upflow is $\sim$47 km s$^{-1}$. The thermal conduction front propagating from BP1 to BP3 was not well identified except for the jet-like motion also originating from BP1.} {We propose that the gentle chromospheric evaporation in the sympathetic CBPs were caused by thermal conduction originating from the primary CBP.}

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