Relativistic Collision Model for Particle Simulation

Summary form only given. For many applications, such as wakefield accelerators and high power microwave tubes, interaction of high energy charged particles with background neutral gas constituents is a key part of the physics. The goal of this work is to extend non-relativistic Monte Carlo collision dynamics to the relativistic regime for computational particle models. In the non-relativistic Monte Carlo package, implemented in XPDP, the probability for collisions in a fixed time step is calculated using random numbers, and the null collision method is applied to reduce the computation load, as an additional operation within the usual PIC charged particle scheme. Based on the non-relativistic collision package, we have developed the relativistic Monte Carlo collision package, introducing the Wentzel model for the cross-section of relativistic elastic collisions and applying relativistic two-body kinematics using four vectors. This model is also compared to a recent relativistic model for several energy regimes. Simulations of a relativistic electron beam are compared with experimental measurements to validate the model