Plasma confinement in multiple mirror systems. II. Experiment and reactor calculation

Abstract

A multiple mirror experiment confirms the predictions of the theory that the axial confinement time exceeds that of a single mirror of the same length, and that the confinement scales as L2, where L is the system length. The experiment indicates that the improved confinement occurs in an intermediate mean free path regime in which the mean free path for scattering out of a loss cone is of the order of a cell length. The absolute value of the axial confinement is smaller than the optimum confinement predicted from the theory by a factor between two and three, which is accounted for by the deviation of experimental parameters from optimum conditions. The scaling of the confinement time with mirror ratio is also investigated. A reactor calculation using the multiple mirror confinement time gives QE = 2 for a 400-m system with 3000-MW(e) output.