Ion-transport theory for a slightly ionized rarefied gas in a strong electric field

A moment solution to the Boltzmann equation is considered for the initial-value problem of a weakly ionized rarefied gas, or gas mixture, in a uniform electric field. No restrictions are placed on the smoothness of the initial data or the mass ratio between the ions and the neutrals although the theory converges fastest for heavy ions in a light gas. A principal result of this theory is the prediction of shock-wave phenomena in pulsed drift tubes. The result is most persistent for heavy ions in a light gas. For instance ${\mathrm{U}}^{+}$ ions in He can be significantly affected by sharp initial conditions for ${10}^4$ collisions. Comparison is made with the results of asymptotic theories to smooth initial data.