CLOUDS-IN-CLOUDS, CLOUDS-IN-CELLS PHYSICS FOR MANY-BODY PLASMA SIMULATION (REPRINTED FROM THE JOURNAL-OF-COMPUTATIONAL-PHYSICS, VOL 3, PG 494-511, 1969)

A clouds-interacting-with-clouds, clouds-in-cells method (CIC) is pres ented for many-body nonlinear plasma problems. Density and force are o btained by assuming that the particles have finite size, are tenuous, and may pass through one another; the particles are thus called clouds . They obey a Coulomb force (similar to 1/r or 1/r(3)) when separated and a linear force (similar to r) when overlapping, allowing simple ha rmonic oscillations at small separation. CIC is contrasted with the ze ro-size particle and nearest-grid-point approach, ZSP-NGP. CIC appears to have substantially less unwanted noise than ZSP-NGP and should be more useful in simulating dense plasmas, Initial runs have been encour aging. The methods may find use in other many-body simulations, such a s with stars, or with particles in phase space. (C) 1969 Academic Pres s.