文章基本信息

标题：2D non-LTE modelling of a filament observed in the H α line with the DST/IBIS spectropolarimeter
本地全文：下载
作者：P. Schwartz ; S. Gunár ; J. M. Jenkins 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2019
卷号：631
页码：1-12
DOI：10.1051/0004-6361/201935358
语种：English
出版社：EDP Sciences
摘要：Context.We study a fragment of a large quiescent filament observed on May 29, 2017 by the Interferometric BIdimensional Spectropolarimeter (IBIS) mounted at the Dunn Solar Telescope. We focus on its quiescent stage prior to its eruption.Aims.We analyse the spectral observations obtained in the Hαline to derive the thermodynamic properties of the plasma of the observed fragment of the filament.Methods.We used a 2D filament model employing radiative transfer computations under conditions that depart from the local thermodynamic equilibrium. We employed a forward modelling technique in which we used the 2D model to produce synthetic Hαline profiles that we compared with the observations. We then found the set of model input parameters, which produces synthetic spectra with the best agreement with observations.Results.Our analysis shows that one part of the observed fragment of the filament is cooler, denser, and more dynamic than its other part that is hotter, less dense, and more quiescent. The derived temperatures in the first part range from 6000 K to 10 000 K and in the latter part from 11 000 K to 14 000 K. The gas pressure is 0.2–0.4 dyn cm−2in the first part and around 0.15 dyn cm−2in the latter part. The more dynamic nature of the first part is characterised by the line-of-sight velocities with absolute values of 6–7 km s−1and microturbulent velocities of 8–9 km s−1. On the other hand, the latter part exhibits line-of-sight velocities with absolute values 0–2.5 km s−1and microturbulent velocities of 4–6 km s−1.
关键词：enSun: filamentsprominencesradiative transferline: profilestechniques: spectroscopicmethods: data analysismethods: numerical