Experimental study of the evolution of H-alpha line profile in a pulse hydrogen discharge

This study reports on experimental technique for investigation of the dynamics of neutrals in direct current hydrogen discharges at low pressures. It is based on analysis of anomalous broadening of the H-alpha emission line profile in a pulsed regime of operation of the source. The application of the technique is relatively simple and it is illustrated in a coaxial discharge tube, but can be readily extended to various discharge sources. The emission line is analyzed by a Fabry-Perot interferometer and therefore high spectral resolution and fast temporal response can be combined. By observing the evolution of the profile with the pulse duration the experimental technique, extended with numerical modelling, gives opportunity for obtaining useful information about the temporal dependence of the processes responsible for formation of the components of the profile.