Recovering Thermodynamics from Spectral Profiles observed by IRIS: A Machine and Deep Learning Approach

Abstract

Inversion codes allow reconstructing a model atmosphere from observations. With the inclusion of optically thick lines that form in the solar chromosphere, such modelling is computationally very expensive because a non-LTE evaluation of the radiation field is required. In this study, we combine the results provided by these traditional methods with machine and deep learning techniques to obtain similar-quality results in an easy-touse, much faster way. We have applied these new methods to Mg II h&k lines observed by IRIS. As a result, we are able to reconstruct the thermodynamic state (temperature, line-of-sight velocity, non-thermal velocities, electron density, etc.) in the chromosphere and upper photosphere of an area equivalent to an active region in a few CPU minutes, speeding up the process by a factor of $10^5$-$10^6$. The open-source code accompanying this paper will allow the community to use IRIS observations to open a new window to a host of solar phenomena.

arXiv comment8 pages, 5 figures

References in corpus (9)

• The Interface Region Imaging Spectrograph (IRIS)
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• Inversion of the radiative transfer equation for polarized light
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• Non-LTE inversions of the Mg II h&k and UV triplet lines
• Magnetic Diagnostics of the Solar Chromosphere with the Mg II h-k Lines
• Partial redistribution in 3D non-LTE radiative transfer in solar atmosphere models

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