Exploring Mutual Information between IRIS Spectral Lines. I. Correlations between Spectral Lines during Solar Flares and within the Quiet Sun.
Exploring Mutual Information between IRIS Spectral Lines. I. Correlations between Spectral Lines during Solar Flares and within the Quiet Sun.
复制标题
探索 IRIS 谱线之间的互信息。
DOI：
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发表时间：
2021
影响因子：
4.9
通讯作者：
S. Voloshynovskiy
中科院分区：
文献类型：
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作者：
Brandon Panos;L. Kleint;S. Voloshynovskiy
光谱线使我们能够探测太阳大气的热力学，但是对于不同的热力学解，单个光谱线的形状可能是相似的。因此，多线分析至关重要，但计算繁琐。我们研究了几个色球和过渡区线之间的相关性，以抑制耀斑期间太阳大气的热力学解。我们使用机器学习方法来捕获来自NASA界面区域成像光谱仪观测到的21个大型太阳耀斑的6条光谱线之间的统计依赖关系。这些技术是基于一个信息理论的数量称为互信息（MI），它捕获的线性和非线性相关谱线之间。使用分类和数值方法估计MI，并分别对安静的太阳和耀斑观测的集合进行。这两种方法返回一致的结果，表明在安静的太阳条件下，光谱线之间的弱相关性，并大大增强了相关性在耀斑条件下，与一些线对，如镁二和C二具有归一化MI分数高达0.5。我们发现，某些谱线耦合比其他更容易，表明在太阳大气中的一致性在许多尺度高度耀斑期间，和所有的线对相关的GOES衍生物，表明相关强度和能量输入之间的正相关关系。我们的方法提供了一个高度稳定和灵活的框架，用于量化太阳大气物理量之间的依赖关系，使我们能够获得其状态的三维图像。
Spectral lines allow us to probe the thermodynamics of the solar atmosphere, but the shape of a single spectral line may be similar for different thermodynamic solutions. Multiline analyses are therefore crucial, but computationally cumbersome. We investigate correlations between several chromospheric and transition region lines to restrain the thermodynamic solutions of the solar atmosphere during flares. We used machine-learning methods to capture the statistical dependencies between six spectral lines sourced from 21 large solar flares observed by NASA’s Interface Region Imaging Spectrograph. The techniques are based on an information-theoretic quantity called mutual information (MI), which captures both linear and nonlinear correlations between spectral lines. The MI is estimated using both a categorical and numeric method, and performed separately for a collection of quiet Sun and flaring observations. Both approaches return consistent results, indicating weak correlations between spectral lines under quiet Sun conditions, and substantially enhanced correlations under flaring conditions, with some line-pairs such as Mg ii and C ii having a normalized MI score as high as 0.5. We find that certain spectral lines couple more readily than others, indicating a coherence in the solar atmosphere over many scale heights during flares, and that all line-pairs are correlated to the GOES derivative, indicating a positive relationship between correlation strength and energy input. Our methods provide a highly stable and flexible framework for quantifying dependencies between the physical quantities of the solar atmosphere, allowing us to obtain a three-dimensional picture of its state.