Ion-hose instability of the relativistic electron beam in rarefied gas

The ionization processes influence on the ion hose instability in the relativistic electron beams propagating through a rarefied gas in the ion1ocused regime is investigated theoretically. The contributions of the collision ionization of the gas in the channel by the beam electrons and channel ions are taken into account, as well as one of the resonant ions charge exchange. The task is solved using the nonlinear kinetic model under the paraxial quasistatic approach for planar geometry of the beam and the channel It is shown that as the gas pressure in the channel rises the instability linear stage characterized by the highest increment prolongs, leading to a higher saturation level of the electron beam mass center oscillations with respect to one at a lower pressure. The prolongation of the resonant linear stage of the instability is assumed to occur due to that reason, that in the considered case of the moderate oscillation amplitudes the new ions production happens mainly as result of the collision ionization by the electrons assisting to the accordance of the beam and the channel distortions.