Magnetic Flux Rope Identification and Characterization from Observationally Driven Solar Coronal Models
Magnetic Flux Rope Identification and Characterization from Observationally Driven Solar Coronal Models
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DOI：
10.3847/1538-4357/aa86b1
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发表时间：
2017-08
期刊：
影响因子：
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通讯作者：
C. Lowder;A. Yeates
中科院分区：
文献类型：
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作者：
C. Lowder;A. Yeates
磁通绳是磁场在日冕中通过剪切重联而形成的，是磁场沿沿着缠绕的扭曲结构。它们的演化和潜在爆发对空间天气具有重要意义。在这里，我们描述了一种新的方法，自动检测磁通绳在模拟磁场中，利用磁力线螺旋度。我们的通量绳探测和组织（FRoDO）代码，它测量随着时间的推移，以及检测喷发的预喷发通量绳的磁通量和螺旋度含量，是公开的。作为第一个演示，该代码被应用于从时间依赖的磁摩擦模型的输出，跨越1996年6月15日至2014年2月10日。在此期间，1561喷发和2099非喷发磁通量绳检测，跟踪和表征。对于这个特定的模型数据，爆发通量绳有一个平均净螺旋度大小Mx2，而非爆发通量绳有一个显着较低的平均Mx2，虽然有重叠的两个分布之间。类似地，喷发通量绳的平均无符号磁通量为Mx，显著高于非喷发通量绳的平均值Mx。这些喷发通量绳的值在观测和理论估计的广泛范围内，尽管在这个特定模型中的喷发率低于观测到的日冕物质抛射。在未来，FRoDO代码将被证明是一个有价值的工具，用于评估不同的非潜在日冕模拟的性能，并将其与观测结果进行比较。
Formed through magnetic field shearing and reconnection in the solar corona, magnetic flux ropes are structures of twisted magnetic field, threaded along an axis. Their evolution and potential eruption are of great importance for space weather. Here we describe a new methodology for the automated detection of flux ropes in simulated magnetic fields, utilizing field-line helicity. Our Flux Rope Detection and Organization (FRoDO) code, which measures the magnetic flux and helicity content of pre-erupting flux ropes over time, as well as detecting eruptions, is publicly available. As a first demonstration, the code is applied to the output from a time-dependent magnetofrictional model, spanning 1996 June 15–2014 February 10. Over this period, 1561 erupting and 2099 non-erupting magnetic flux ropes are detected, tracked, and characterized. For this particular model data, erupting flux ropes have a mean net helicity magnitude of Mx2, while non-erupting flux ropes have a significantly lower mean of Mx2, although there is overlap between the two distributions. Similarly, the mean unsigned magnetic flux for erupting flux ropes is Mx, significantly higher than the mean value of Mx for non-erupting ropes. These values for erupting flux ropes are within the broad range expected from observational and theoretical estimates, although the eruption rate in this particular model is lower than that of observed coronal mass ejections. In the future, the FRoDO code will prove to be a valuable tool for assessing the performance of different non-potential coronal simulations and comparing them with observations.