Caesium plasma transport properties

Abstract

The transport properties of a caesium gas are computed for the temperature range of 350-10,000°K and for pressures of 1 atm to 10-6 mm Hg. Values of electrical, thermal and viscosity transport coefficients are determined. The thermoelectric coefficients are also determined. The extensively developed theory for gas mixture transport properties, which solves the Boltzmann equation with the assumption of binary collisions, is employed. The Debye length is used as the cut-off in the coulomb collision integrals and convergence of the solution for each transport property as a function of the degree of approximation is determined for all degrees of ionization. Experimental data for caesium are used to find values for the collision integrals for ion-atom and atom-atom interactions. Theoretical expressions are used for electron-atom and charged particle interactions. Results of the calculations indicate that at low pressure and small ionization the thermoelectric coefficient α exhibits a maximum. In the slightly ionized region the value of the zero current thermal conductivity K' is found to be dependent on ion-atom interactions as well as electron-atom interactions. The thermal conductivity K is found to differ from K' at degrees of ionization as low as 10-4. Ion-atom interactions influence the viscosity in the partially ionized region. Electron-atom interactions dominate the electrical conductivity in the partially ionized region.