Theoretical and experimental investigations of the growth of a large-scale instability in the discharge of an XeCl laser with UV preionisation

A theoretical investigation was made of an instability of a pulsed self-sustained discharge in an XeCl laser with magnetic-spiker excitation. Use was made of a one-dimensional model in calculation of the spatiotemporal distributions of the plasma components — electrons, Xe⁺, Xe^*, HCl(v = 0, 1, 2, 3, …) — and of the photon distribution in the laser cavity. The conditions were found for energy deposition in the discharge so as to ensure its homogeneity and stable prolonged ( ~300 ns) existence in an enclosure of 50 mm × 33 mm × 820 mm dimensions. These conditions were satisfied in experiments involving pumping of an XeCl laser with the aid of simple spark UV preionisation. The efficiency of conversion of the electrical energy, stored in pulse-forming lines and in a prepulse generator, into the optical energy was ~3.6% and the energy of the output radiation pulses was ~3.6 J. Theoretical and experimental studies were made of the influence of the electrode profile and of the geometry of the return current conductors on the XeCl laser characteristics.