Ion beam modeling using ARGUS

Over the past several years, the ARGUS code has been used to simulate a variety of ion beam phenomena. ARGUS is a general purpose three-dimensional simulation code. It can handle fields-only electromagnetic and electrostatic simulations, as well as electrostatic (steady-state and time-dependent) and electromagnetic time-dependent particle-in-cell (PIC) simulations. In the fields-only electromagnetic regime, ARGUS can be run in the time domain as well as the frequency domain (eigenmodes). The steady-state electrostatic PIC model is essentially a three-dimensional gun code. This paper will present results of using the steady-state PIC module in ARGUS to model two related ion beam devices that use electrostatic quadrupole fields to focus and accelerate an H⁻ ion beam. The results of simulations of Lawrence Berkeley Laboratory´s (LBL) Constant-Current Variable-Voltage (CCW) H⁻ accelerator will be presented first. For this device, ARGUS has been used to simulate electron trapping and H⁻ stripping between the ion source and the CCW accelerator, acceleration and transport through the CCW modular electrostatic, discrete quadrupole sections. The second device is a helical electrostatic quadrupole used for low-energy beam transport in the SSC.