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In this paper the results of a theoretical analysis on the properties of electric discharges used in high-power molecular lasers are presented. The mathematical model is based on continuity and transport equations for electrons and ions and on the equations concerning the electric field. The model is used both for self-sustained and for non-selfsustained discharges operating in conditions as usually attained in high-power lasers. Spatial profiles of the electrical parameters near the electrodes and in the plasma area are assessed. Current-voltage characteristics are finally derived for a He∶N2∶CO2∶CO laser mixture. A future work will be devoted both to the kinetic and to the fluid-dinamic model of the laser and to a comparison of the numerical results obtained with available experimental data.

Part I of the paper—devoted to modelling high-power CW lasers—gives a brief description of the investigated device and uses an analytical approximation to Bethe’s formula to calculate the following quantities: the space profiles in the discharge chamber of the electron beam energy, the stopping power and the source term under operating conditions for four-component mixtures of practical interest. The energy loss of the primary beam in travelling through a thin Al foil is calculated. Parts II and III will be published promptly. Part II will be devoted to the plasma characteristics in the discharge chamber and to the kinetic and fluid-dynamic model of the laser. Part III will be devoted to an assessment of the numerical results obtained from the model and their comparison with experimental data.