[en] One of main problems in accelerator physics is the increasing of ion beam intensity. The linear undulator accelerator with electrostatic undulator (UNDULAC-E) was proposed for ion beam acceleration. The accelerating force in UNDULAC is produced by an electric field which is a combination of two or more spatial harmonics, none of them being synchronous with the ion beam. In UNDULAC-E one of RF field space harmonic and field of electrostatic undulator are used. The value of this force is proportional to the particle charge squared. This effect allows neutralizing the beam space charge by accelerating ions with opposite charge sign within the same bunch. In this paper some results of analytical and numerical study beam space charge neutralization in UNDULAC-E using transverse electrostatic undulator are represented.