A SYNTHETICALLY ACCELERATED SCHEME FOR RADIATIVE-TRANSFER CALCULATIONS

Recently, we have developed a one-dimensional radiation-hydrodynamics code called SARA (Synthetically Accelerated Radiation-Hydrodynamics Al gorithm) which solves the multigroup radiation transport equations imp licitly. A high order differencing scheme as well as multifrequency gr ey synthetic acceleration techniques are used to obtain a robust algor ithm that can be used for a large variety of energy transport problems . The advantages of such an algorithm are, first, that it solves the t rue (S(n)) transport equations, secondly, a positive differencing sche me which verifies the asymptotic diffusion limit is used, and, finally , the S(n) equations are accelerated by the S2 synthetic acceleration method, which allows the acceleration of high order schemes in plane a nd curvilinear geometries. The code has been validated with some Marsh ak wave propagation problems found in the bibliography, and successful ly used to simulate the conversion experiments of laser and ion beams into X-rays.