Excitation of electrostatic solitary waves during neutralization of ion beam pulse by plasma

The possibility of exciting electrostatic solitary waves (ESWs) during the neutralization of ion beam pulses by plasmas is investigated using a two-dimensional (2D) electrostatic particle-in-cell (PIC) code. The simulation results show that if an axial magnetic field is applied, an ESW can be excited when the ion beam enters the plasma. The ESW is caused by the phase space vortex motion of electrons in the potential well formed by the plasma and the ion beam. The ESW is very stable and has a very long lifetime when it propagates in the plasma and the ion beam. The ESW has a 2D space structure, with about 3 cm length and more than twice the width of the ion beam. The splitting of the ESW is observed when it encounters a potential drop. The excitation conditions of the ESW are also discussed.