Multiframe nitrogen laser for diagnostics of a plasma produced by means of relativistic electron beam accelerators

A four-frame system for laser probing of a plasma using molecular nitrogen as an active medium is developed and manufactured. The laser reliability operated at approximately 13000 Pa nitrogen pressure in the spark gap and at a discharge voltage of 25 kV. The pulse duration made up 6 ns, energy in the pulse was equal to approximately 1 mJ. The beam divergence was determined by the discharge geometry and made up approximately 1/50. The results obtained when using this system in experiments on explosion of tungsten filaments 50 mm in diameter in the Triton facility are presented. Processing the experimental results has revealed that a medium velocity of plasma filament expansion made up 5x105 cm/s. Till a certain moment of time the plasma column expanded without a visible distortion of the boundary stability. In this case its diameter approached approximately 0.4 mm. Nonuniformities in the plasma filament did not arise at once over the whole length, but only near the cathode. Development of the instability was followed by appearance of soft X-radiation which also trended to concentrate in the cathode region