One dimensional simulations of transients in heavy ion injectors

A fast-running time-dependent one-dimensional particle code has been developed to simulate transients in both electrostatic quadrupole and electrostatic column heavy-ion injectors. Two-dimensional effects are incorporated through the use of an approximation to the transverse part of the Laplacian operator. Longitudinal electric fields are solved on a mesh. An external circuit is coupled to the column, and the effect of the beam on the circuit is modeled. Transients such as initial current spikes, space-charge debunching, and beam loading of the circuit, are simulated. Future directions for the code include introduction of envelope and centroid equations to provide beam radius and displacement information and the modeling of secondary electron currents arising from beam-spill.