Schwartz, P;
Gunar, S;
Jenkins, JM;
Long, DM;
Heinzel, P;
Choudhary, DP;
(2019)
2D non-LTE modelling of a filament observed in the H_alpha line with the DST/IBIS spectropolarimeter.
Astronomy & Astrophysics
, 631
, Article A146. 10.1051/0004-6361/201935358.
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Abstract
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. We analyse the spectral observations obtained in the H$\alpha$ line to derive the thermodynamic properties of the plasma of the observed fragment of the filament. 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 producesynthetic H_alpha line 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. 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 6,000 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}^{2} in the first part and around 0.15 dyn/cm}^{2} in 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 and microturbulent velocities of 8-9 km/s. On the other hand, the latter part exhibits line-of-sight velocities with absolute values 0-2.5 km/s and microturbulent velocities of 4-6 km/s.
| Type: | Article |
|---|---|
| Title: | 2D non-LTE modelling of a filament observed in the H_alpha line with the DST/IBIS spectropolarimeter |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1051/0004-6361/201935358 |
| Publisher version: | http://dx.doi.org/10.1051/0004-6361/201935358 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10085086 |
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