# MONTE CARLO RADIATION-HYDRODYNAMICS WITH IMPLICIT METHODS

## Abstract

We explore the application of Monte Carlo transport methods to solving coupled radiation-hydrodynamics (RHD) problems. We use a time-dependent, frequency-dependent, three-dimensional radiation transport code that is special relativistic and includes some detailed microphysical interactions such as resonant line scattering. We couple the transport code to two different one-dimensional (non-relativistic) hydrodynamics solvers: a spherical Lagrangian scheme and a Eulerian Godunov solver. The gas–radiation energy coupling is treated implicitly, allowing us to take hydrodynamical time-steps that are much longer than the radiative cooling time. We validate the code and assess its performance using a suite of radiation hydrodynamical test problems, including ones in the radiation energy dominated regime. We also develop techniques that reduce the noise of the Monte Carlo estimated radiation force by using the spatial divergence of the radiation pressure tensor. The results suggest that Monte Carlo techniques hold promise for simulating the multi-dimensional RHD of astrophysical systems.

- Authors:

- Physics Department, University of California, Berkeley, CA 94720 (United States)

- Publication Date:

- OSTI Identifier:
- 22519943

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Astrophysical Journal, Supplement Series; Journal Volume: 217; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; FREQUENCY DEPENDENCE; HYDRODYNAMICS; LAGRANGIAN FUNCTION; MONTE CARLO METHOD; RADIANT HEAT TRANSFER; RADIATION PRESSURE; RADIATION TRANSPORT; RADIATIVE COOLING; RELATIVISTIC RANGE; SCATTERING; TENSORS; TIME DEPENDENCE

### Citation Formats

```
Roth, Nathaniel, and Kasen, Daniel, E-mail: nathaniel.roth@berkeley.edu.
```*MONTE CARLO RADIATION-HYDRODYNAMICS WITH IMPLICIT METHODS*. United States: N. p., 2015.
Web. doi:10.1088/0067-0049/217/1/9.

```
Roth, Nathaniel, & Kasen, Daniel, E-mail: nathaniel.roth@berkeley.edu.
```*MONTE CARLO RADIATION-HYDRODYNAMICS WITH IMPLICIT METHODS*. United States. doi:10.1088/0067-0049/217/1/9.

```
Roth, Nathaniel, and Kasen, Daniel, E-mail: nathaniel.roth@berkeley.edu. Sun .
"MONTE CARLO RADIATION-HYDRODYNAMICS WITH IMPLICIT METHODS". United States.
doi:10.1088/0067-0049/217/1/9.
```

```
@article{osti_22519943,
```

title = {MONTE CARLO RADIATION-HYDRODYNAMICS WITH IMPLICIT METHODS},

author = {Roth, Nathaniel and Kasen, Daniel, E-mail: nathaniel.roth@berkeley.edu},

abstractNote = {We explore the application of Monte Carlo transport methods to solving coupled radiation-hydrodynamics (RHD) problems. We use a time-dependent, frequency-dependent, three-dimensional radiation transport code that is special relativistic and includes some detailed microphysical interactions such as resonant line scattering. We couple the transport code to two different one-dimensional (non-relativistic) hydrodynamics solvers: a spherical Lagrangian scheme and a Eulerian Godunov solver. The gas–radiation energy coupling is treated implicitly, allowing us to take hydrodynamical time-steps that are much longer than the radiative cooling time. We validate the code and assess its performance using a suite of radiation hydrodynamical test problems, including ones in the radiation energy dominated regime. We also develop techniques that reduce the noise of the Monte Carlo estimated radiation force by using the spatial divergence of the radiation pressure tensor. The results suggest that Monte Carlo techniques hold promise for simulating the multi-dimensional RHD of astrophysical systems.},

doi = {10.1088/0067-0049/217/1/9},

journal = {Astrophysical Journal, Supplement Series},

number = 1,

volume = 217,

place = {United States},

year = {Sun Mar 15 00:00:00 EDT 2015},

month = {Sun Mar 15 00:00:00 EDT 2015}

}