Plasmas-gases of electrically charged particles-are one of the most complex fluids encountered in nature. Because of the long-range nature of the electric and magnetic interactions between plasma electrons and the ions composing them, plasmas exhibit a wide variety of collective forms of motions, for example, coherent motions of large number of electrons, ions, or both. This leads to an extremely rich physics of plasmas. Plasma particle-in-cell (PIC) simulation codes have proven to be a powerful tool for the study of complex nonlinear plasma problems in many areas of plasma physics research such as space and astrophysical plasmas, magnetic and inertial confinement, free electron lasers, electron and ion beam propagation and particle accelerators. In PIC codes, the orbits of thousands to millions of interacting plasma electrons and ions are followed in time as the particles move in electromagnetic fields calculated self-consistently from the charge and current densities created by these same plasma particles.

We developed an algorithm, called the *general concurrent
particle-in-cell algorithm* (GCPIC) for implementing PIC codes
efficiently on MIMD parallel computers [Liewer:89c]. This
algorithm was first used to implement a well-benchmarked [Decyk:88a]
one-dimensional electrostatic PIC code. The benchmark problem, used to
benchmark the Mark IIIfp, was a simulation of an electron beam plasma
instability ([Decyk:88a], [Liewer:89c]). Dynamic load
balancing has been implemented in a
one-dimensional electromagnetic GCPIC code
[Liewer:90a]; this code was used to study electron
dynamics in magnetosonic shock waves in space
plasmas [Liewer:91a]. A two-dimensional electrostatic PIC code
has also been implemented using the GCPIC algorithm with and without
dynamic load balancing [Ferraro:90b;93a].
More recently, the two-dimensional electrostatic
GCPIC code was extended to an electromagnetic code [Krucken:91a]
and used to study parametric instabilities of large amplitude Alfvén
waves in space plasmas [Liewer:92a].

Wed Mar 1 10:19:35 EST 1995