Dynamics of cusp produced rotating beam

The advent of the cusptron and the peniotron tubes have renewed interest in the axis-rotating electron beam. One of the most successful methods of producing the axis-encircling beam is by magnetic cusp injection . This paper examines the fundamental properties of the cusp dynamics by using simplified, but still realistic, models that assess the effects of the various experimental parameters in terms of gain reduction, and attempts to devise experimentally realizable optimum beam configurations. Special emphases are given to off-centering sources, and methods to reduce them. The single particle orbit equation is solved using simple approximations from which the effects of several field contributing factors are examined. The experimental factors considered are the magnetic field profiles including the degree of the field reversal, the cusp transition thickness, and the adiabatic compression after the transition