Multi-Term Boltzmann Analysis of Electrons in N2.
Final rept. 1 Oct 79-30 Sep 80,
JOINT INST FOR LAB ASTROPHYSICS BOULDER CO
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A multi-term spherical harmonic expansion method was previously developed for the numerical solution of the Boltzmann transport equation in the context of electron swarm analysis. Here, the method is used to investigate the validity of the more usual two-term spherical harmonic expansion in nitrogen. The multi-term method has also been used to study the effects of ionization and anisotropic cross-sections. Studies are given of the convergence of swarm parameters using the Boltzmann code and the effects of boundaries by comparing the Boltzmann results with Monte Carlo studies in nitrogen at moderate field strengths. These calculations were done using a set of cross-sections previously derived from swarm experiments and the fields were constrained to be low enough that secondary electrons resulting from ionization were safely ignored. The extension of the calculations to higher fields was accomplished by using higher energy cross-sections than available from the swarm data and by slight modification of the computational techniques. The effect of anisotropic scattering was investigated and found to be negligible at low field strengths but quite important at the one higher field of 500 Townsends that was investigated. Calculations are presented for field strengths high enough that 50 of the electron energy loss is to ionization. Implications of these results are discussed. Author
- Physical Chemistry
- Numerical Mathematics