ION DEFOCUSING IN MULTICUSP PLASMA-CONFINEMENT SYSTEMS

The proposed Polywell polyhedral multicusp plasma confinement systems are designed to achieve strong ion focusing to a radius rc ≪ R. In this letter, a phenomenon is indicated that may tend to limit the attainable degree of focusing. This defocusing effect should be taken into account when estimating the feasible regimes of operation. Although it may not preclude successful operation of polyhedral multicusp devices, it may limit the attainable convergence.