Development of axisymmetric rf focusing effects for an ion linac

Abstract

High intensity ion beam dynamics in an axisymmetric rf focusing acceleration structure is considered. New equations of particles motion in polyharmonic rf field are devised by means of smooth approximation. Analysis of these equations allows one to formulate the conditions of beam stability. A new approach to rf focusing acceleration channel parameters choice is suggested. The relationship between 4D phase space volume of the bunch and transmission is studied by means of Hamiltonian analysis. The influence of the space charge on rf focusing conditions, transmission, longitudinal and transverse emittances, and other acceleration system characteristics is investigated by computer simulation. The “superparticles” method is being applied. The efficiency of the approach is confirmed by numerical simulation.