3-DIMENSIONAL ELECTROMAGNETIC PARTICLE-IN-CELL WITH MONTE-CARLO COLLISION SIMULATIONS ON 3 MIMD PARALLEL COMPUTERS

A three-dimensional electromagnetic particle-in-cell code with Monte C arlo collision (PIC-MCC) is developed for MIMD parallel supercomputers . This code uses a standard relativistic leapfrog scheme incorporating Monte Carlo calculations to push plasma particles and to include coll isional effects on particle orbits. A local finite-difference time-dom ain method is used to update the self-consistent electromagnetic field s. The code is implemented using the General Concurrent PIC (GCPIC) al gorithm, which uses domain decomposition to divide the computation amo ng the processors. Particles must be exchanged between processors as t hey move among subdomains. Message passing is implemented using the Ex press Cubix library and the PVM. We evaluate the performance of this c ode using a 512-processor Intel Touchstone Delta, a 512-processor Inte l Paragon, and a 256-processor CRAY T3D. It is shown that a high paral lel efficiency exceeding 95% has been achieved on all three machines f or large problems. We have run PIC-MCC simulations using several hundr ed million particles with several million collisions per time step. Fo r these large-scale simulations the particle push time achieved is in the range of 90-115 ns/particle/time step, and the collision calculati on time in the range of a few hundred nanoseconds per collision.