  CSNS/RCS accelerates a high-intensity proton beam from 80 MeV to 1.6 GeV.
Since the beam current and beam power is high, the beam loading is a severe
problem for the stability of the circulating beam in the RCS. To study the beam
loading effect in the CSNS/RCS theoretically, the RLC circuit model of the rf
cavity, the method of the Fast Fourier Transform and the method of Laplace
transform have been employed to obtain the impedance of the rf system, the beam
spectrum and the beam-induced voltage, respectively. Based on these physical
models, the beam dynamics equations have been revised and a beam loading model
has been constructed in the simulation code ORIENT. By using the code, the beam
loading effect on the rf system of the CSNS/RCS has been investigated. Some
simulation results have been obtained and conclusions have been drawn.
