Two-body similarity and its violation in tokamak edge plasmas

Scaling laws found under the assumption that two-body collisions dominate can be effectively used to benchmark complex multi-dimensional codes dedicated to investigating tokamak edge plasmas. The applicability of such scaling laws to the interpretation of experimental data, however, is found to be restricted to the relatively low plasma densities (<10(19) m(-3)) at which multistep processes, which break the two-body collision approximation, are unimportant. (C) 1996 American Institute of Physics.