A generalization of critical velocity concept to neutral or charged particles and beams in neutral and/or partially ionized collisional cases

Summary form only given. This paper attempts to extend Alfven's critical velocity for almost collisionless counter-streaming neutral and plasma beams to neutral or charged particles and beams streaming in neutral and/or partially ionized collisional gases. It is indicated that such an extended concept of critical ionization velocity can be applied to a number of discharge and ionization phenomena in space and in the laboratory for their explanations, such as basic streamer and leader phenomena, rocket and tower triggered lightning, cloud-to-ionosphere electrical discharges, tornadic thunderstorms, planetary and nebular lightning, and ball lightning and often as a manifestation of joint effects of electric reconnection and critical velocity.