PREDICTED ELECTRON-TRANSPORT COEFFICIENTS AT HIGH E-N-VALUES .1. HYDROGEN

Transport coefficients of electrons in hydrogen are calculated over the range 10-16≤E/N≤2.9×10-15 V cm2 by solving the Boltzmann equation using a two-term spherical-harmonic expansion which takes into account the effect of the source of new electrons produced by ionization. Recently reported electron cross-section data, both experimental and theoretical, have been used in the calculation. It is shown that the release of new electrons in ionizing collisions has a noticeable effect on the electron distribution function starting from E/N≃1.2×10-15 V cm2. The predicted values of the first Townsend ionization coefficient are in excellent agreement with experimental results over the entire range of E/N values considered without using unrealistically large momentum-transfer cross sections at high electron energies. The calculated values for the drift velocity vd are in good agreement with the measured values. For the characteristic energy DT/μ, the agreement is good up to E/N=2×10-15 V cm2, while for higher E/N it becomes less satisfactory. The electron excitation rates for the vibration, the excitation of the B 1Σ+u and C 1Πu electronic states, and the rate of H-atom production are presented as a function of E/N. Results are also given for the fraction of the input power that is transfered to the various inelastic processes.