| Abstract: | The one-dimensional flows of an inviscid plasma not in thermal equilibrium and with a variable degree of ionization are investigated in the absence of currents. A criterion showing when the ordinary equations of gasdynamics may be used to describe these flows is given. An expression is found for the velocity of sound in such a plasma. Under certain conditions it passes into Newton's formula for isothermal sound. The condition fulfilled in the critical cross section of the channel is found. It is established that the flow of a weakly ionized plasma occurs at constant electron temperature. A detailed investigation is made of the possible types of flow in a cylindrical channel.A criterion is given which shows when the model of a plasma in thermal equilibrium may be applied, and also relationships which permit complete calculation of the flow of such a plasma in a channel of variable cross section.Generally speaking, the flow of a plasma with no currents present differs from the flow of a nonionized gas. This difference is related to the processes of ionization and recombination taking place in the plasma. The electrons usually play the main part in these processes, and so the average energies (temperatures) of electrons and heavy particles (atoms and ions) may differ. If the inelastic collision frequency in the plasma is small compared with the elastic collision frequency, then the temperature difference between the electron component and the heavy component of the plasma may be considerable. The simplest cases of one-dimensional plasma flows are considered with account for ionization and recombination processes and in the absence of thermal equilibrium among the components.The author is grateful to M. N, Kogan for discussing the paper. |
