Spatio-temporal dynamics of charged species in the afterglow of plasma containing negative ions

Summary form only given. The spatio-temporal evolution of charged species densities and wall fluxes during the afterglow of an electronegative discharge have been investigated. It was found that decay of plasma with negative ions is quite different than that of electropositive plasma. Decay of plasma with negative ions consists of two surges. During first stage electrons dominate plasma diffusion and negative ions are trapped inside by the static electric field: the flux of negative ions to the walls is nearly zero. The electron escape frequency is considerably increased in the presence of negative ions, and can eventually approach free electron diffusion. During the second stage of the afterglow, electrons have disappeared and positive and negative ions diffuse to the walls with the ion-ion ambipolar diffusion coefficient.