Relaxation of the volume charge created by the electron flow in the air

The process of relaxation of the volume electric charge formed by high-energy electrons in air is considered. The charge carriers are negative ions formed when thermalized electrons attach to oxygen molecules. A mathematical model of ion drift in an electric field is built, based on the charge continuity law and Maxwell's equations. The algorithm for the numerical solution of the model equations is based on the particle method. A numerical estimate of the relaxation time of the volume charge is carried out.