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arXiv 1607.02008astro-ph.SR
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日冕辐射时滞分析中的定常加热特征

Signatures of Steady Heating in Time Lag Analysis of Coronal Emission

Nicholeen M. Viall, James A. Klimchuk

摘要:

在研究日冕加热的许多方法中,Viall & Klimchuk(2012)的时间滞后方法作为传统使用的分析技术的补充变得越来越普遍。时滞方法交叉相关的光曲线在一个给定的空间位置获得的光谱带,样品不同的温度等离子体。它最广泛地用于太阳动力学观测站大气成像组件的数据。我们之前已经将时间滞后方法应用于整个活动区域和周围安静的太阳,并创建结果地图(Viall & Klimchuk 2012; Viall & Klimchuk 2015)。我们发现,大部分的时间滞后是一致的冷却日冕等离子体已被脉冲加热。此外,地图区域的很大一部分具有零时滞。这并不表示缺乏可变性。相反,强可变性必须存在,并且它必须在不同通道中同步发生。我们之前已经表明,这些零时间滞后与过渡区对日冕纳米耀斑的响应一致(Viall & Klimchuk 2015; Bradshaw & Viall 2016),但其他解释也是可能的。一个常见的误解是,零时间滞后表明稳定的排放是由于稳定的加热。使用模拟和观察到的光变曲线,我们在这里证明,高度相关的光变曲线在零时滞是不兼容的平衡解决方案。这样的光变曲线只能通过进化来创造。

英文摘要:

Among the many ways of investigating coronal heating, the time lag method of Viall & Klimchuk (2012) is becoming increasingly prevalent as an analysis technique complementary to those traditionally used. The time lag method cross correlates light curves at a given spatial location obtained in spectral bands that sample different temperature plasmas. It has been used most extensively with data from the Atmospheric Imaging Assembly on the Solar Dynamics Observatory. We have previously applied the time lag method to entire active regions and surrounding quiet Sun and create maps of the results (Viall & Klimchuk 2012; Viall & Klimchuk 2015). We find that the majority of time lags are consistent with the cooling of coronal plasma that has been impulsively heated. Additionally, a significant fraction of the map area has a time lag of zero. This does not indicate a lack of variability. Rather, strong variability must be present, and it must occur in phase in the different channels. We have shown previously that these zero time lags are consistent with the transition region response to coronal nanoflares (Viall & Klimchuk 2015; Bradshaw & Viall 2016), but other explanations are possible. A common misconception is that the zero time lag indicates steady emission resulting from steady heating. Using simulated and observed light curves, we demonstrate here that highly correlated light curves at zero time lag are not compatible with equilibrium solutions. Such light curves can only be created by evolution.

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