MONTE-CARLO ANALYSIS OF THE ELECTRONS MOTION IN A SEGMENTED HOLLOW-CATHODE DISCHARGE

We have investigated the motion of electrons in a new, high voltage se gmented hollow cathode discharge, which is known to be an efficient pu mping source for charge-transfer excited UV metal ion lasers. We have studied the spatial distribution of ion production, electron energy di stributions, statistics of electron avalanches, the fraction of oscill ating electrons, and the distribution of the fast electrons' current o n the anode surface in a helium discharge having four electrode segmen ts. We have found that the ion production is strongly peaked in the ce ntre of the discharge due to the focusing cathode geometry. The effect of magnetic field on the characteristics of the discharge was also st udied. With increasing magnetic field the peak of the spatial distribu tion of ionization was split into two regions of high ionization rate. Furthermore, due to the magnetic field, at fixed discharge current th e number of high-energy electrons absorbed on the anode increased cons iderably, and a higher number of primary electrons were absorbed by th e anode without making any ionization. At constant discharge voltage t he fraction of oscillating electrons was found to decrease, due to the applied longitudinal magnetic field. The magnetic field dependence of the spatial distribution of ion production, the energy distribution o f electrons absorbed by the anode and the fraction of oscillating elec trons at different discharge conditions were also studied in a dischar ge having six electrode segments.