Hybrid radiation hydrodynamics scheme with adaptive gravity-tree-based pseudo-particles

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Název: Hybrid radiation hydrodynamics scheme with adaptive gravity-tree-based pseudo-particles
Autoři: Lau, Cheryl S. C., Petkova, Maya, 1990, Bonnell, Ian A.
Zdroj: Monthly Notices of the Royal Astronomical Society. 538(3):1461-1480
Témata: radiative transfer, software: simulations, HII regions, hydrodynamics, methods: numerical
Popis: H ii regions powered by ionizing radiation from massive stars drive the dynamical evolution of the interstellar medium. Fast radiative transfer methods for incorporating photoionization effects are thus essential in astrophysical simulations. Previous work by Petkova et al. established a hybrid radiation hydrodynamics (RHD) scheme that couples smoothed particle hydrodynamics (SPH) to grid-based Monte Carlo radiative transfer (MCRT) code. This particle-mesh scheme employs the Exact mapping method for transferring fluid properties between SPH particles and Voronoi grids on which the MCRT simulation is carried out. The mapping, however, can become computationally infeasible with large numbers of particles or grid cells. We present a novel optimization method that adaptively converts gravity tree nodes into pseudo-SPH particles. These pseudo-particles act in place of the SPH particles when being passed to the MCRT code, allowing fluid resolutions to be temporarily reduced in regions which are less dynamically affected by radiation. A smoothing length solver and a neighbour-finding scheme dedicated to tree nodes have been developed. We also describe the new heating and cooling routines implemented for improved thermodynamic treatment. We show that this tree-based RHD scheme produces results in strong agreement with benchmarks, and achieves a speed-up that scales with the reduction in the number of particle-cell pairs being mapped.
Popis souboru: electronic
Přístupová URL adresa: https://research.chalmers.se/publication/545676
https://research.chalmers.se/publication/545676/file/545676_Fulltext.pdf
Databáze: SwePub
Popis
Abstrakt:H ii regions powered by ionizing radiation from massive stars drive the dynamical evolution of the interstellar medium. Fast radiative transfer methods for incorporating photoionization effects are thus essential in astrophysical simulations. Previous work by Petkova et al. established a hybrid radiation hydrodynamics (RHD) scheme that couples smoothed particle hydrodynamics (SPH) to grid-based Monte Carlo radiative transfer (MCRT) code. This particle-mesh scheme employs the Exact mapping method for transferring fluid properties between SPH particles and Voronoi grids on which the MCRT simulation is carried out. The mapping, however, can become computationally infeasible with large numbers of particles or grid cells. We present a novel optimization method that adaptively converts gravity tree nodes into pseudo-SPH particles. These pseudo-particles act in place of the SPH particles when being passed to the MCRT code, allowing fluid resolutions to be temporarily reduced in regions which are less dynamically affected by radiation. A smoothing length solver and a neighbour-finding scheme dedicated to tree nodes have been developed. We also describe the new heating and cooling routines implemented for improved thermodynamic treatment. We show that this tree-based RHD scheme produces results in strong agreement with benchmarks, and achieves a speed-up that scales with the reduction in the number of particle-cell pairs being mapped.
ISSN:00358711
13652966
DOI:10.1093/mnras/staf366