Genre: Information/Explanation

Operating system : NLTSS , VMS , UNIX , MAC OS , DOS . Keywords : Boltzmann equation , Electron distribution , Transport coeffcients , Physics laser , Plasma physics , Gas discharges , Kinetic model . Classification : 19.8 , 19.11 . Nature of problem : ELENDIF calculates the time evolution of the electron energy distribution function in a mixture of partially ionized gases with or without an applied electric field . The code can treat inelastic and superelastic processes , electron-electron and electron-ion collisions , photon-electron ( free-free ) processes , attachment and recombination , ionization including a distribution of secondary electrons , and an external source of electrons ( e.g. an electron beam ) . The code also computes the mean electron energy , drift velocity , diffusion coefficient , rate coefficients and energy flow rates for the processes being included in the calculation . Solution method : ELENDIF solves the time-dependent Boltzmann transport equation in terms of the electron number density . By finite-differencing the electron energy axis , the Boltzmann equation is transformed into a finite set of coupled differential equations for the electron number density at each energy grid as a function of time . The matrix of densities is then evolved forward in time using a combination of explicit and implicit methods . The electron energy distribution is then convolved with the cross section to provide the transport coefficients , collisional rates and energy flow rates . Restrictions : It is assumed in the formulation of ELENDIF that the two-term spherical harmonic expansion of the electron distribution function is adequate . Running time : On the Vax 8650 the code takes 0.11 seconds per timestep if the effects of electron-electron collisions are ignored , and 0.46 seconds per timestep if electron-electron collisions are included .