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arXiv 0905.3462astro-ph.SR
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耀斑活动区中心苔藓的流动和运动:稳定加热的证据

Flows and Motions in Moss in the Core of a Flaring Active Region: Evidence for Steady Heating

David H. Brooks, Harry P. Warren

摘要:

我们提出了新的测量的时间变化的强度,多普勒和非热的苔藓在活动区的核心观察到的EUV成像光谱仪在2007年6月日。测量结果来自Fe 12 195A线的光谱轮廓。使用2 "狭缝,我们在几分钟内重复扫描150" × 150 "。这是第一次有可能在苔藓中进行这种速度测量,所提供的数据是有史以来在日冕中获得的苔藓多普勒和非热速度的最高节奏空间分辨地图。观测到的区域产生了许多C级和M级耀斑,其中有几个发生在靠近苔藓的核心。因此,磁场在活动区核心明显地发生了变化,所以如果苔藓中存在动态特征,我们应该能够检测到它们。我们的测量苔藓强度同意与以前的研究中,一个小于15%的变异性是在16小时内看到的。我们对多普勒和非热速度的新测量显示,苔藓中没有强烈的流动或运动,这些量也没有任何显著的变化。结果证实,高温冕环底部的苔藓是准稳定加热的。他们还表明,准稳态加热可以作出显着的贡献,即使在核心的耀斑生产活动区。这种加热在高频率下可能是脉冲的,但如果是这样,它不会引起大的流动或运动。

英文摘要:

We present new measurements of the time variability of intensity, Doppler and non-thermal velocities in moss in an active region core observed by the EUV Imaging Spectrometer on Hinode in 2007, June. The measurements are derived from spectral profiles of the Fe 12 195A line. Using the 2" slit, we repeatedly scanned 150" by 150" in a few mins. This is the first time it has been possible to make such velocity measurements in the moss, and the data presented are the highest cadence spatially resolved maps of moss Doppler and non-thermal velocities ever obtained in the corona. The observed region produced numerous C- and M- class flares with several occurring in the core close to the moss. The magnetic field was therefore clearly changing in the active region core, so we ought to be able to detect dynamic signatures in the moss if they exist. Our measurements of moss intensities agree with previous studies in that a less than 15% variability is seen over a period of 16 hours. Our new measurements of Doppler and non-thermal velocities reveal no strong flows or motions in the moss, nor any significant variability in these quantities. The results confirm that moss at the bases of high temperature coronal loops is heated quasi-steadily. They also show that quasi-steady heating can contribute significantly even in the core of a flare productive active region. Such heating may be impulsive at high frequency, but if so it does not give rise to large flows or motions.

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