A mathematical study of the electron decay in diffusion and recombination controlled afterglows

摘要: Abstract The continuity equation for electrons in a decaying plasma is solved numerically three dimensions including loss term quadratic the electron density (i.e., two-body electron-ion recombination) and an ambipolar diffusion term. geometries investigated are finite cylinder, rectangular parallelepiped, some one-dimensional cases. densities averaged assuming weighting functions corresponding to various microwave probing field distributions (cylindrical TM 010 , TE 011 111 retangular 101 modes) therefore directly proportional measured quantities, such as resonant frequency shifts, obtained afterglow studies of recombination. Three different initial used, uniform (recombination controlled), fundamental mode somewhat more spatially constricted distribution. linear range computed (averaged densities) −1 -versus-time curves determined correction factors derived which, if applied observations, yield corrected recombination coefficients from curves. corrections two- three-dimensional analyses found be significantly larger than those analyses. Also, when considering containers shapes but same length, surface/volume ratio equivalent effect increased coefficient predicted decays. In most cases practical interest, though, much stronger dependence upon varying container or cavity compared. When present analysis geometries, agreement with results Gray Kerr obtained.