Generation of plasma electron halo by a charged particle beam in a low density plasma

Abstract

Breaking of a plasma wave driven by a long beam of charged particles results in electron jets escaping from the plasma column and forming an electron halo. The halo is accompanied by a strong radial electric field around the plasma, which can distort the trajectories of relativistic charged particles that propagate near the plasma border or are injected into the plasma wave. We study the mechanisms of wave breaking and halo formation when the beam and plasma densities are comparable. If the plasma density is less than or of the order of the beam density, the wavebreaking is well described by a semi-analytical model, which agrees with simulations and allows us to calculate the position of wavebreaking points and determine the regions around the plasma column occupied by the halo.