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arXiv 0910.0458astro-ph.SR
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定常加热的证据:对具有Hinode和TRACE的活动区核心的观测

Evidence for Steady Heating: Observations of an Active Region Core with Hinode and TRACE

Harry P. Warren, Amy R. Winebarger, David H. Brooks

摘要:

先前的观测无法排除高温活动区环实际上是由许多处于不同加热和冷却阶段的小尺度线程组成的可能性,并且似乎只是处于平衡状态。利用极紫外成像光谱仪(EIS)和X射线望远镜(XRT)对\textit{Hinode}的新观测,我们有能力对高温日冕等离子体的性质进行非常详细的研究。我们研究的排放在一个活跃的区域的核心,并找到三个独立的证据线稳定加热。我们发现,在XRT中观察到的发射通常是稳定的数小时,在一个单独的像素约15%的波动水平。观察到短暂的脉冲加热事件,但它们似乎是无关的稳定的排放占主导地位的活动区域。此外,我们发现没有证据表明温暖的排放,是空间相关的热排放,如预期的,如果高温循环是脉冲加热的结果。最后,我们还发现,强度的“苔藓”,高温回路的足点,是一致的稳定加热模型,只要我们考虑到局部膨胀的循环从基地的过渡区的日冕。结合起来,这些结果提供了强有力的证据表明,在一个活跃的区域的核心加热是有效的稳定,也就是说,加热事件之间的时间相对于相关的辐射和传导冷却时间短。

英文摘要:

Previous observations have not been able to exclude the possibility that high temperature active region loops are actually composed of many small scale threads that are in various stages of heating and cooling and only appear to be in equilibrium. With new observations from the EUV Imaging Spectrometer (EIS) and X-ray Telescope (XRT) on \textit{Hinode} we have the ability to investigate the properties of high temperature coronal plasma in extraordinary detail. We examine the emission in the core of an active region and find three independent lines of evidence for steady heating. We find that the emission observed in XRT is generally steady for hours, with a fluctuation level of approximately 15% in an individual pixel. Short-lived impulsive heating events are observed, but they appear to be unrelated to the steady emission that dominates the active region. Furthermore, we find no evidence for warm emission that is spatially correlated with the hot emission, as would be expected if the high temperature loops are the result of impulsive heating. Finally, we also find that intensities in the "moss", the footpoints of high temperature loops, are consistent with steady heating models provided that we account for the local expansion of the loop from the base of the transition region to the corona. In combination, these results provide strong evidence that the heating in the core of an active region is effectively steady, that is, the time between heating events is short relative to the relevant radiative and conductive cooling times.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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