Asteroid Defence: Radiation deposition profiles for angle and depth

In this work we study the energy and momentum deposited to a hazardousnear-earth object due to the radiation (photons) from a nuclear stand-offburst. We use an adaptive-mesh hydrocode, which models the radiationvia nonequilibrium diffusion, to investigate the deposition profiles at varyingdepths and angles, and we compare these results to the analytic work byAhrens and Harris. For the problem of interest, the radiation mean-free-path is exceedingly small (O(1 mm)) compared to the size of the asteroid(O(100 m)), and the radiation is dominantly absorbed by those parts of theasteroid that are closest to the nuclear source. We present a time-dependentanalysis of the radiation-energy and radiation-momentum deposition, as wellas the resolution of the mesh, and a demonstration of the convergence of ourresults.