Monte Carlo simulations of charged particle transport in plasmas: A fast single-scattering model

When simulating a charged particle trajectory in plasmas with Monte Carlo methods, the traditional single-scattering model is accurate but computationally expensive. The traditional multiple-scattering model reduces the computation cost but assumes an exponential distribution of the scattering angle, which overestimates the cumulative scattering angle. In this paper, we develop a new Monte Carlo method for the charged particle transport simulations. The scattering angle is naturally sampled from a modified screened Rutherford scattering cross section, in which a greatly amplified minimum deflection angle is used. With this model, the simulations give the same scattering angle distribution with the single-scattering model but only take a comparable computation cost with the multiple-scattering model when the small scattering angle and Markovian approximations can be fulfilled. This model would be especially useful for the study of inertial-confinement-fusion, which is sensitive to the alpha-particle energy deposition.