Volume 631, November 2019
|Number of page(s)||14|
|Section||Numerical methods and codes|
|Published online||23 October 2019|
Non-LTE radiation hydrodynamics in PLUTO⋆
Dipartimento di Fisica e Chimica, Université degli Studi di Palermo, via Archirafi 36, Palermo, Italy
2 LERMA, Observatoire de Paris, Sorbonne Université, Université de Cergy-Pontoise, CNRS, Paris, France
3 INAF – Osservatorio Astronomico di Palermo, Palermo, Italy
4 Universidad de Las Palmas de Gran Canaria, Gran Canaria, Spain
5 Université Paris Diderot, Sorbonne Paris Cité, AIM, UMR 7158, CEA, 91191 Gif-sur-Yvette, France
Accepted: 5 July 2019
Context. Modeling the dynamics of most astrophysical structures requires an adequate description of the interaction of radiation and matter. Several numerical (magneto-) hydrodynamics codes were upgraded with a radiation module to fulfill this request. However, those that used either the flux-limited diffusion (FLD) or the M1 radiation moment approaches are restricted to local thermodynamic equilibrium (LTE). This assumption may not be valid in some astrophysical cases.
Aims. We present an upgraded version of the LTE radiation-hydrodynamics (RHD) module implemented in the PLUTO code, which we have extended to handle non-LTE regimes.
Methods. Starting from the general frequency-integrated comoving-frame equations of RHD, we have justified all the assumptions that were made to obtain the non-LTE equations that are implemented in the module under the FLD approximation. An operator-split method with two substeps was employed: the hydrodynamics part was solved with an explicit method by the solvers that are currently available in PLUTO, and the non-LTE radiation diffusion and energy exchange part was solved with an implicit method. The module was implemented in the PLUTO environment. It uses databases of radiative quantities that can be provided independently by the user: the radiative power loss, and the Planck and Rosseland mean opacities. In our case, these quantities were determined from a collisional-radiative steady-state model, and they are tabulated as functions of temperature and density.
Results. Our implementation has been validated through different tests, in particular, radiative shock tests. The agreement with the semi-analytical solutions (when available) is good, with a maximum error of 7%. Moreover, we have proved that a non-LTE approach is of paramount importance to properly model accretion shock structures.
Conclusion. Our radiation FLD module represents a step toward a general non-LTE RHD modeling.
Key words: radiation: dynamics / hydrodynamics / opacity
The module is available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/631/A41 and upon request to the first author.
© ESO 2019
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.