Adaptive ray tracing for radiative transfer around point sources

By Tom Abel, Benjamin Dan Wandelt. 2001

136 citations recorded by the source corpus.

We describe a novel adaptive ray tracing scheme to solve the equation of radiative transfer around point sources in hydrodynamical simulations. The angular resolution adapts to the local hydrodynamical resolution and hence is of use for adaptive meshes as well as adaptive smooth particle hydrodynamical simulations. Recursive creation of rays ensures ease of implementation. The multiple radial integrations needed to solve the time-dependent radiative transfer are speeded up significantly using a quad-tree once the rays are cast. Simplifications advantageous for methods with one radiation source are briefly discussed. The suggested method is easily generalized to speed up Monte Carlo radiative transfer techniques. In summary, a nearly optimal use of long characteristics is presented and aspects of its implementation and comparison with other methods are given.

Subfields: Computational Mechanics, Computer Graphics and Computer-Aided Design

View Paper: https://www.semanticscholar.org/paper/adda784577bd679e4ecb0592c4563802e07f74b6

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Citations in the corpus

The birth of a galaxy – II. The role of radiation pressure (2012, methodology): “The radiation field is evolved with adaptive ray tracing (Abel & Wandelt 2002; Wise & Abel 2011) that is based on the HEALPix framework (Górski et al. 2005) and is coupled self-consistently to the hydrodynamics.”
THE BIRTH OF A GALAXY: PRIMORDIAL METAL ENRICHMENT AND STELLAR POPULATIONS (2010, methodology): “Stellar feedback The radiation field is evolved with adaptive ray tracing (Abel & Wandelt 2002; Wise & Abel 2011) that is based on the HEALPix framework (Górski et al. 2005) and is coupled self-consistently to the hydrodynamics.”
IONIZING PHOTON ESCAPE FRACTIONS FROM HIGH-REDSHIFT DWARF GALAXIES (2008, methodology): “We have modified the code to include a time-dependent implementation of radiative transfer that adaptively ray traces from point sources (Abel & Wandelt 2002; Abel et al. 2007; Wise & Abel 2008a).”
Comparison of reionization models: radiative transfer simulations and approximate, seminumeric models (2010, methodology): “It uses the HEALPix-based adaptive raysplitting scheme of Abel & Wandelt (2002), such that rays split as they travel to ensure that a minimum number of rays reach each cell.”
Dusty Star Forming Galaxies at High Redshift (2014, background): “…the complex dust infrared emission from stars, molecular clouds and dust grains over a wide range of galaxy geometries and luminosities (Silva et al., 1998; Chary and Elbaz, 2001; Dale et al., 2001; Dale and Helou, 2002; Abel and Wandelt, 2002; Siebenmorgen and Krügel, 2007; Draine and Li, 2007).”
The birth of a galaxy – III. Propelling reionization with the faintest galaxies (2014, methodology): “The hydrogen ionizing radiation emitted during main sequence are propagated with adaptive ray tracing (Abel & Wandelt 2002; Wise & Abel 2011) that is based on the HEALPIX framework (Górski et al. 2005).”
Resolving the Formation of Protogalaxies. II. Central Gravitational Collapse (2007, methodology): “Also, the technique of adaptive ray tracing (Abel & Wandelt 2002) has been implemented into Enzo and used to study the outflows and ionizing radiation from a primordial star (Abel et al. 2007).”
Resolving the Formation of Protogalaxies. III. Feedback from the First Stars (2007, methodology): “We use adaptive ray tracing (Abel & Wandelt 2002) to overcome this dilemma associated with ray tracing (cf. Abel et al. 2007).”
Simulations and Analytic Calculations of Bubble Growth during Hydrogen Reionization (2006, methodology): “With the ionizing sources and cosmological density field in hand, we trace rays of ionizing photons through the simulation box using the adaptive ray-tracing scheme of Abel & Wandelt (2002), and the code of Sokasian et al. (Sokasian et al. 2001; Sokasian et al. 2003).”
Cosmological radiative transfer codes comparison project – I. The static density field tests (2006, unknown): “The point source algorithm is an extension of the adaptive ray-splitting scheme of Abel & Wandelt (2002) to a model with variable grid resolution, with all discretization done on the grid.”
The morphology of H ii regions during reionization (2006, methodology): “Rays are split adaptively using the HealPIX algorithm (Abel & Wandelt 2002) such that, at a minimum, N rays from a source intersect every cell face (for this paper, we set N = 2.1).”
ENZO: AN ADAPTIVE MESH REFINEMENT CODE FOR ASTROPHYSICS (2013, methodology): “We avoid this inefficiency by utilizing adaptive ray tracing (Abel & Wandelt 2002), which is based on Hierarchical Equal Area isoLatitude Pixelation (HEALPix; Górski et al. 2005) and progressively splits rays when the sampling becomes too coarse.”
Modeling UV Radiation Feedback from Massive Stars. II. Dispersal of Star-forming Giant Molecular Clouds by Photoionization and Radiation Pressure (2018, methodology): “The radiative transfer of ionizing and non-ionizing photons is handled by the adaptive ray tracing method (Abel & Wandelt 2002).”
Absorption-line systems in simulated galaxies fed by cold streams (2011, methodology): “…calculations, but due to the numerical complexity of this problem, codes that solve the (approximated) RT equation (e.g. Gnedin & Abel 2001; Abel & Wandelt 2002) together with the hydrodynamic equations has been developed and used only recently (e.g. Razoumov et al. 2006; Petkova &…”
He ii REIONIZATION AND ITS EFFECT ON THE INTERGALACTIC MEDIUM (2008, methodology): “…Nray = 12×4 L rays are cast with L = 5 or 6 for an isotropically emitting source, with these rays uniformly pixelating the unit sphere using the HealPIX algorithm as described in Abel & Wandelt (2002).4 Each source must wait for all of the other sources to send a ray before it sends a second ray.”
ramses-rt: radiation hydrodynamics in the cosmological context (2013, background): “Adaptive ray tracing (e.g. Abel & Wandelt 2002; Razoumov & Cardall 2005; Wise & Abel 2011) is a variant on long characteristics, where rays of photons are integrated outwards from the source, updating the ray at every step of the way via absorption.”
Cosmic reionization by stellar sources: population III stars (2003, methodology): “To speed up the calculations further, the ray-casting scheme used in Sokasian et al. (2001) has been modified to incorporate an adaptive scheme based on the method described by Abel & Wandelt (2002).”
Far-infrared spectral energy distribution fitting for galaxies near and far (2012, background): “…in recent years to model the dust infrared emission of stars, molecular clouds and starburst galaxies over a wide range of bolometric luminosities (Silva et al. 1998; Chary & Elbaz 2001; Dale et al. 2001; Dale & Helou 2002; Abel & Wandelt 2002; Siebenmorgen & Krügel 2007; Draine & Li 2007).”