Modeling of Deuterium Ionization and Extraction From an Ion Source Driven by Heated Cathode

A new simple predictor-corrector method for stationary self-consistent electrostatic field modeling is developed on the basis of Comsol Multiphysics 3.5 capabilities. The method is implemented in the script written in Comsol Script 1.3. The basic idea of the method is iterative computation of space charge density from a set of virtually traced trajectories of charged particles. The script is tailored for modeling of charged particle movement in a cylindrically symmetric self-consistent stationary electric field of a gas-filled DD-neutron tube with an ion source driven by a heated cathode. The proposed approach is useful for determining the mode of operation of a tube (whether plasma is formed in ion source or the mode of operation is plasmaless) and for verification of design modifications for plasmaless neutron tubes. The computed charge fields are shown to be self-consistent with a space charge adjustment error of 2.5% at worst.