Radiative Equilibrium and Temperature Correction in Monte Carlo Radiation Transfer

By J. Bjorkman, K. Wood. 2001

262 citations recorded by the source corpus.

We describe a general radiative equilibrium and temperature correction procedure for use in Monte Carlo radiation transfer codes with sources of temperature-independent opacity, such as astrophysical dust. The technique utilizes the fact that Monte Carlo simulations track individual photon packets, so we may easily determine where their energy is absorbed. When a packet is absorbed, it heats a particular cell within the envelope, raising its temperature. To enforce radiative equilibrium, the absorbed packet is immediately reemitted. To correct the cell temperature, the frequency of the reemitted packet is chosen so that it corrects the temperature of the spectrum previously emitted by the cell. The reemitted packet then continues being scattered, absorbed, and reemitted until it finally escapes from the envelope. As the simulation runs, the envelope heats up, and the emergent spectral energy distribution (SED) relaxes to its equilibrium value without iteration. This implies that the equilibrium temperature calculation requires no more computation time than the SED calculation of an equivalent pure scattering model with fixed temperature. In addition to avoiding iteration, our method conserves energy exactly because all injected photon packets eventually escape. Furthermore, individual packets transport energy across the entire system because they are never destroyed. This long-range communication, coupled with the lack of iteration, implies that our method does not suffer the convergence problems commonly associated with Λ-iteration. To verify our temperature correction procedure, we compare our results with standard benchmark tests, and finally we present the results of simulations for two-dimensional axisymmetric density structures.

Subfields: Astronomy and Astrophysics, Atmospheric Science, Civil and Structural Engineering

View Paper: https://www.semanticscholar.org/paper/c8460ebe9c92792281334e4aabc476535c23e376

How researchers see this paper

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

In Astronomy and Astrophysics

In Atmospheric Science

In Civil and Structural Engineering

Citations in the corpus

Two-dimensional Radiative Transfer in Protostellar Envelopes. II. An Evolutionary Sequence (2003, methodology): “It uses the radiative equilibrium solution method of Bjorkman & Wood (2001) incorporated into a 3-”
Modelling the spectral energy distribution of galaxies - V. The dust and PAH emission SEDs of disk galaxies (2010, background): “…developed for use in other astrophysical contexts (Mattila 1970, Witt 1977, Yusef-Zadeh 1984, Wood et al. 1996, Lucy 1999, Wolf et al. 1999, Bjorkman & Wood 2001, Steinackeret al. 2003, Wolf 2003, Juvela 2005, Steinacker et al. 2006, Fritz et al. 2006). the centre to up to 2 kpc in the…”
MOCASSIN: a fully three-dimensional Monte Carlo photoionization code (2002, background): “Bjorkman & Wood (2001) have described a general radiative equilibrium and temperature correction procedure for use in Monte Carlo radiative transfer codes having sources of temperatureindependent opacity, such as dust.”
LIMITING ACCRETION ONTO MASSIVE STARS BY FRAGMENTATION-INDUCED STARVATION (2010, methodology): “RADMC-3D is based on the standard Monte Carlo method of Bjorkman & Wood (2001) in combination with Lucy’s method of treating optically thin regions (Lucy 1999).”
Fitting the integrated spectral energy distributions of galaxies (2010, background): “Here, the temperature of the grains is updated with the absorption and emission of each photon (described in detail in Bjorkman and Wood 2001; Baes et al. 2005).”
The warm gas atmosphere of the HD 100546 disk seen by Herschel - Evidence of a gas-rich, carbon-poor atmosphere? (2012, methodology): “In such cases, the approximative PDF given in Bjorkman & Wood (2001) is used.”
Probing dust grain evolution in IM Lupi's circumstellar disc. Multi-wavelength observations and mo (2008, methodology): “This step uses the algorithms described in Bjorkman & Wood (2001) and Lucy (1999) with a total number of 1 280 000 photon packets.”
The Inner Regions of Protoplanetary Disks (2010, methodology): “In particular the Monte Carlo methods of Lucy (1999) and of Bjorkman & Wood (2001) have proven to be ideally suited for this problem, and by far most models today use these techniques or variants of them.”
Three-Dimensional Dust Radiative Transfer ∗ (2013, unknown): “…technique or frequency distribution adjustment technique emits dust thermal photons immediately after each absorption event in a specific grid cell, with the wavelength of the emitted thermal dust photon carefully chosen to retain thermal equilibrium (Bjorkman & Wood 2001; Baes et al. 2005).”
PROTOPLANETARY DISK STRUCTURES IN OPHIUCHUS (2009, methodology): “RADMC utilizes an algorithm similar to the one described by Bjorkman & Wood (2001) to simulate the propagation of photons through a dust medium that is heated solely by irradiation (in this case from the central star).”
The dusty heart of nearby active galaxies. II. From clumpy torus models to physical properties of dust around active galactic nuclei (2009, methodology): “For that, we apply the noniterative method delineated by Bjorkman & Wood (2001), based on work by Lucy (1999).”
Radiative transfer modeling of three-dimensional clumpy AGN tori and its application to NGC 1068 (2006, methodology): “Our radiative transfer codemcsim mpi is based on the Monte Carlo approach by Bjorkman & Wood (2001).”
Radiative transfer in very optically thick circumstellar disks (2009, methodology): “The required flexibility for radiative transfer can be obtained by using a Monte Carlo method (see e.g. Bjorkman & Wood 2001; Niccolini et al. 2003; Pinte et al. 2006).”
Interpreting Spectral Energy Distributions from Young Stellar Objects. I. A Grid of 200,000 YSO Model SEDs (2006, methodology): “For the grid of models presented here, we ran each model with 20,000,000 ‘photons’ (energy packets, Bjorkman & Wood 2001).”
Survival of molecular gas in cavities of transition disks - I. CO (2013, methodology): “In the first stage, the dust temperature is obtained using a method combining the algorithm by Bjorkman & Wood (2001) and Lucy (1999).”