Spatial-time behavior of transversally excited pulsed volume discharge in argon is investigated by spontaneous emission
spectroscopy and different imaging techniques. VUV Ar2* emission, UV-VIS continuum and Ar* red lines are used for
direct monitoring of discharge homogeneity in the breakdown and recombination stages. Experimental data indicate that
Ar* atoms and Ar2* excimers are created exclusively in the positive column of the discharge, not in near-cathode zones.
These zones (cathode sheath and negative glow), however, are the main sources of UV-VIS continuum. The discharge is
homogeneous during the first powerful breakdown pulse and fills the whole space between electrodes. Secondary
excitation pulses initiate oscillations of plasma emission and longitudinal fragmentation of the discharge into separate
zones. Fragmentation is connected with dynamical change of the electron emittance of heated and cold electrodes.
Additional electrons, produced during secondary excitation pulses, convert effectively the reservoir of long-lived triplet
Ar2* molecules to fast-emitted singlet Ar2* excimers - sharp spikes of VUV (126 nm) emission are observed. Double-pulse
discharge pumping regime is suggested for easier achievement of the lasing threshold for rare gas excimer lasers.
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