On the coupling of electron energy distribution function and excited state distributions in pulsed microwave H $\mathsf{_{2}}$ plasmas

Abstract

Time evolution of vibrationally and electronically excited states and their coupling with the electron energy distribution function (EEDF) were calculated for microwave pulsed discharges. Different situations have been considered by changing the period and the duty cycle, and considering different pressure values.The main result of this study was to evidence the change in the non-equilibrium character and dynamics of the different distributions depending on the pressure and the pulse period. In particular EEDF strongly deviating from the Maxwell behaviour appear as a consequence of inelastic and superelastic collisions at relatively high pressure and long period. Also, strong oscillation appears on the tail of the H2 vibrational distribution at high pressure discharge conditions. At low pressure, the effect of superelastic and inelastic collisions appears to be less significant and most of the plasma characteristics may be deduced from a time averaged electron energy distribution function.