Volume Forces in Plasmas

Abstract

A formula is derived for the force exerted by charged particles on neutral particles in a gaseous discharge. It is shown that (a) the discussions of Langmuir and Druyvesteyn with respect to the reaction force on the neutral gas particles resulting from the net rate of momentum transfer by the charged particles to the wall of the discharge tube are incomplete and (b) the expression for the force postulated by Leiby is a limiting case of a more general form of the force equation. The calculations also show that the presence of discharge container walls is not required for the existence of volume forces in contrast with the theories presented by Langmuir and Druyvesteyn.