Evolution of the Beam Emittance in Linear Induction Accelerator with Discrete Focusing System

The paper analyzes the evolution of the emittance of a kiloampere electron beam in a linear induction accelerator (LIA) with a discrete focusing system in order to assess the possibility of its application as a driver for generating radiation according to the free electron laser (FEL) scheme. In this analysis, special attention is paid to the geometry and parameters of the electron injector, the entry of particles from which into the accelerating structure of such an LIA mainly determines the characteristics of the beam at its exit. The features of the transverse dynamics of the beam during its passage through this accelerating structure are studied. The influence of various factors contributing to an increase in the beam emittance at the output of the LIA is considered. Analytical estimates of the beam parameters are compared with the results of numerical simulation. Based on the results of comparing the measured beam emittance with its value obtained in numerical simulation, it was concluded that the beam parameters are adequate for pumping terahertz oscillations in the FEL cavity