Dynamics of cusp produced rotating beam

Abstract

The cusptron is based on an axis-encircling beam produced by magnetic cusp injection. The fundamental properties of the cusp dynamics have been examined by using simplified, but still realistic, models that assess the effects of various experimental parameters in terms of gain reduction. An attempt has been made to devise experimentally realizable optimum beam configurations. Special emphasis is given to off-centering sources and methods to reduce them. The single particle orbit equation has been solved using simple approximations from which the effects of several field contributing factors are examined. The experimental factors considered were the magnetic field profiles, including the degree of the field reversal, the cusp transition thickness, and the adiabatic compression after the transition. It has been found that the unbalanced field effect generally contributes most to the off-centering and that adiabatic compression after the cusp reduces both the beam radius and the off-centering effect. The features of an optimum magnetic field are given.<>