Stopping and thermalization of interpenetrating plasma streams

The interpenetration of two supersonically moving plasmas is affected by both collective modes of oscillation and Coulomb collisions. Two potentially important plasma instabilities, an electrostatic ion two stream and an electromagnetic ion Weibel, are considered and shown to be stabilized if only a small fraction of ion kinetic energy is converted to heat. For low‐density, highly supersonic flows, the mean free path for slowing down (dominated in most cases of interest by ion–ion collisions) can be larger than or comparable to the system size. To develop an understanding of these plasmas, a unique hydrodynamic model has been developed that allows interpenetration but explicitly converts kinetic energy into heat as the ions slow down. The model is applied to the collision of two plasmas created by heating two parallel foils.