Hybrid Adaptive Ray-Moment Method (HARM$^2$): A Highly Parallel Method for Radiation Hydrodynamics on Adaptive Grids

摘要

We present a highly-parallel multi-frequency hybrid radiation hydrodynamicsalgorithm that combines a spatially-adaptive long characteristics method forthe radiation field from point sources with a moment method that handles thediffuse radiation field produced by a volume-filling fluid. Our Hybrid AdaptiveRay-Moment Method (HARM$^2$) operates on patch-based adaptive grids, iscompatible with asynchronous time stepping, and works with any moment method.In comparison to previous long characteristics methods, we have greatlyimproved the parallel performance of the adaptive long-characteristics methodby developing a new completely asynchronous and non-blocking communicationalgorithm. As a result of this improvement, our implementation achievesnear-perfect scaling up to $\mathcal{O}(10^3)$ processors on distributed memorymachines. We present a series of tests to demonstrate the accuracy andperformance of the method.