Asteroid Defence: Radiation deposition profiles for angle and depth

Abstract:

In this work we study the energy and momentum deposited to a hazardous
near-earth object due to the radiation (photons) from a nuclear stand-off
burst. We use an adaptive-mesh hydrocode, which models the radiation
via nonequilibrium diffusion, to investigate the deposition profiles at varying
depths and angles, and we compare these results to the analytic work by
Ahrens 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 the
asteroid that are closest to the nuclear source. We present a time-dependent
analysis of the radiation-energy and radiation-momentum deposition, as well
as the resolution of the mesh, and a demonstration of the convergence of our
results.