Use of a dye laser to produce shadowgraph patterns of the plasma of a laser spark

Experimental results are reported on the use of a dye laser with an output wavelength at the H/sub ..cap alpha../ line to produce shadowgraph projections of a laser spark plasma in hydrogen. Information on the zone in which the resonance radiation is absorbed in the plasma is obtained. A study is made of the evolution of the shock wave over a broad pressure range.