Methods for increasing of beam intensity in undulator linear accelerator

The paper describes theoretical problems of ion focusing and acceleration in the high-intensity undulator linear accelerator (UNDULAC), where the accelerating force is produced by a combination of a radiofrequency field and undulator field. Both electrostatic and magnetostatic undulators are studied. The main factor limiting the beam intensity in the ion accelerator is space-charge forces. Three methods for increasing of the ion beam intensity in UNDULAC are discussed: (i) enlarging of the beam cross-section; (ii) acceleration of several beams in one RF structure; (iii) compensation of the space charge by acceleration of ions with different signs of the charge in the same bunch