Microsoft Word - Welch_TOPPJ

We describe a particle advance algorithm for particle-in-cell simulation of highly magnetized charged particles that relaxes the time step constraint due to cyclotron motion. The method preserves the correct cyclotron radius for large time steps and corrects for magnetic field gradients without requiring explicit calculation of the particle magnetic moment. Application of the algorithm is illustrated with electron and ion single particle orbit calculations in a field reversed configuration with rotating magnetic fields. This technique is efficient and applicable to massively parallel simulation.