Keys P H, Steiner O, Vigeesh G
Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, UK.
Leibniz-Institut für Sonnenphysik (KIS), Schöneckstrasse 6, 79104 Freiburg, Germany.
Philos Trans A Math Phys Eng Sci. 2021 Feb 8;379(2190):20200182. doi: 10.1098/rsta.2020.0182. Epub 2020 Dec 21.
Stokes inversion codes are crucial in returning properties of the solar atmosphere, such as temperature and magnetic field strength. However, the success of such algorithms to return reliable values can be hindered by the presence of oscillatory phenomena within magnetic wave guides. Returning accurate parameters is crucial to both magnetohydrodynamics (MHD) studies and solar physics in general. Here, we employ a simulation featuring propagating MHD waves within a flux tube with a known driver and atmospheric parameters. We invert the Stokes profiles for the 6301 Å and 6302 Å line pair emergent from the simulations using the well-known Stokes Inversions from Response functions code to see if the atmospheric parameters can be returned for typical spatial resolutions at ground-based observatories. The inversions return synthetic spectra comparable to the original input spectra, even with asymmetries introduced in the spectra from wave propagation in the atmosphere. The output models from the inversions match closely to the simulations in temperature, line-of-sight magnetic field and line-of-sight velocity within typical formation heights of the inverted lines. Deviations from the simulations are seen away from these height regions. The inversions results are less accurate during passage of the waves within the line formation region. The original wave period could be recovered from the atmosphere output by the inversions, with empirical mode decomposition performing better than the wavelet approach in this task. This article is part of the Theo Murphy meeting issue 'High-resolution wave dynamics in the lower solar atmosphere'.
斯托克斯反演代码对于恢复太阳大气的特性(如温度和磁场强度)至关重要。然而,此类算法返回可靠值的成功可能会受到磁波导内振荡现象的阻碍。返回准确的参数对于磁流体动力学(MHD)研究和一般的太阳物理学都至关重要。在此,我们采用了一个模拟,该模拟在具有已知驱动源和大气参数的通量管内传播MHD波。我们使用著名的响应函数斯托克斯反演代码对模拟中出现的6301 Å和6302 Å线对的斯托克斯轮廓进行反演,以查看对于地基天文台的典型空间分辨率,是否能够恢复大气参数值。即使在大气中波传播导致光谱出现不对称的情况下,反演也能返回与原始输入光谱相当的合成光谱。反演的输出模型在反演线的典型形成高度范围内,在温度、视线磁场和视线速度方面与模拟结果紧密匹配。在这些高度区域之外可以看到与模拟结果的偏差。在线形成区域内波通过期间,反演结果的准确性较低。通过反演可以从大气输出中恢复原始波周期值,在这项任务中经验模式分解比小波方法表现更好。本文是西奥·墨菲会议文集“太阳低层大气中的高分辨率波动动力学”的一部分。