Leak width of a cusp-confined plasma

The theoretical and numerical steady-state calculation of the width of an escaping plasma stream through a magnetic mirror solves the self-consistent potential and charge distribution for a low beta plasma. The leak widths is obtained as the geometric mean of the ion and electron Larmor radius, also called hybrid width, in agreement with some experimental measurements. If the out-streaming plasma is unstable or collisional, the leak width can only larger, contrary to earlier results in the literature. (orig.)