SPECTROSCOPIC STUDY OF A SUPERSONIC JET OF LASER-HEATED ARGON PLASMA

A spectroscopic study of a low-pressure supersonic jet of laser-heated argon plasma is presented. The experimental set-up consisted of a hig h-pressure convergent nozzle and a supersonic nozzle. The supersonic n ozzle was placed just behind the convergent nozzle and was connected t o a low-pressure chamber. A continuous wave CO2 laser with output powe r of 2 kW was used to maintain the plasma in the stream of argon gas f lowing from the convergent nozzle. The plasma then expanded through th e supersonic nozzle. Emission spectra from the laser-sustained plasma and supersonic jet were measured with a 1.3 m focal length spectrograp h and 1254 silicon intensified target (SIT) detector connected to an E G&G PARC optical multichannel analyser (OMA) III. We found that the su personic stream of argon plasma had an electron density of 6 x 10(14)- 10(15) Cm(-3)and a temperature of 6-7 kK.