MOCASSIN: a fully three-dimensional Monte Carlo photoionization code

By Barbara Ercolano, M. Barlow, P. Storey, Xiao-Wei Liu. 2002

175 citations recorded by the source corpus.

The study of photoionized environments is fundamental to many astrophysical problems. Up to the present most photoionization codes have numerically solved the equations of radiative transfer by making the extreme simplifying assumption of spherical symmetry. Unfortunately very few real astronomical nebulae satisfy this requirement. To remedy these shortcomings, a self-consistent, three-dimensional radiative transfer code has been developed using Monte Carlo techniques. The code, MOCASSIN, is designed to build realistic models of photoionized nebulae having arbitrary geometry and density distributions, with both the stellar and diffuse radiation fields treated self-consistently. In addition, the code is capable of treating one or more exciting stars located at non-central locations. The gaseous region is approximated by a cuboidal Cartesian grid composed of numerous cells. The physical conditions within each grid cell are determined by solving the thermal equilibrium and ionization balance equations. This requires a knowledge of the local primary and secondary radiation fields, which are calculated self-consistently by locally simulating the individual processes of ionization and recombination. The structure and the computational methods used in the MOCASSIN code are described in this paper. MOCASSIN has been benchmarked against established one-dimensional spherically symmetric codes for a number of standard cases, as defined by the Lexington/Meudon photoionization workshops: at Meudon in 1985 and at Lexington in 1995 and 2000. The results obtained for the benchmark cases are satisfactory and are presented in this paper. A performance analysis has also been carried out and is discussed here.

Subfields: Aerospace Engineering, Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d2cc19040bda798c39029f92853f8c4a4b8de679

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Aerospace Engineering

In Astronomy and Astrophysics

Citations in the corpus

Radiation-hydrodynamic models of X-ray and EUV photoevaporating protoplanetary discs (2009, methodology): “This parametrization is based on the results of 3D Monte Carlo radiative transfer calculations us- c© 2002 RAS, MNRAS 000, 1–16 ing mocassin (Ercolano et al. 2003, 2005, 2008a).”
THE EFFECT OF LINE-OF-SIGHT TEMPERATURE VARIATION AND NOISE ON DUST CONTINUUM OBSERVATIONS (2009, methodology): “MOCASSIN is a 3D code that uses a Monte Carlo approach to the transfer of radiation through an arbitrary medium (Ercolano et al. 2003, 2008).”
The Hα surface brightness–radius relation: a robust statistical distance indicator for planetary nebulae (2015, background): “D photoionization codes (e.g. Ercolano et al. 2003) allows the self-consistent determination of the PN structure, central 4 The Mach number is defined asM = v/vs , wherev is the velocity of the object relative to the ambient gas andvs is the sound velocity in the gas.”
X-Ray-Irradiated Protoplanetary Disk Atmospheres. I. Predicted Emission-Line Spectrum and Photoevaporation (2008, methodology): “…and self-consistent model of irradiated gaseous T Tauri disks, we employ a fully 3D photoionisation and dust radiative transfer code, mocassin (Ercolano et al., 2003, 2005, 2008), to calculate the detailed ionisation and temperature structure of a typical T Tauri disk, with special emphasis…”
The dusty MOCASSIN: fully self-consistent 3D photoionization and dust radiative transfer models (2005, methodology): “We present here a new version (2.0) of the 3D photoionization code MOCASSIN (Ercolano et al. 2003a, hereafter Paper I), designed to achieve the above by employing a stochastic approach to simultaneously solve the dust and gas RT.”
Massive stars in massive clusters II: Disruption of bound clusters by photoionization (2012, methodology): “We will describe this technique in detail in Dale and Ercolano (2012), in prep, and validate it by comparison with the Monte Carlo radiative transfer code mocassin (Ercolano et al. 2003, 2005, 2008).”
Protoplanetary disc evolution and dispersal: the implications of X-ray photoevaporation (2010, methodology): “(Stone & Norman 1992) to calculate the hydrodynamical evolution of the disc, where the gas temperature due to Xray irradiation is parametrised as a function of ionisation parameter using the 3D radiative transfer code mocassin (Ercolano et al 2003, 2005, 2008).”
On the theory of disc photoevaporation (2011, methodology): “…wind (obtained from a hydrodynamic calculation using an ionization parameter approach) was fed in to the MOCASSIN Monte Carlo radiative transfer code (Ercolano et al. 2003, 2008; Ercolano, Barlow & Storey 2005), which self-consistently follows the attenuation and propagation of X-ray photon…”