Temporally resolved schlieren images of a laser-generated plasma

Temporally resolved images of a long-scalelength aluminum plasma (L /spl ges/ 100 /spl mu/m, 10/sup 19/ cm/sup -3/ /spl les/ n/sub e/ /spl les/ 10/sup 20/ cm/sup -3/, T/sub e/ /spl ap/ T/sub i/ /spl ap/ 50 eV, Z~ /spl ap/ 8.5) were obtained with a charge coupled device camera using the schlieren diagnostic technique. The schlieren imaging probe beam was a 15-mm diameter, 5-mJ, 266-nm, 110-ns FWHM laser pulse that uniformly illuminated the plasma. The probe beam was fired at various times relative to the plasma formation beam on a shot-to-shot basis, and refracted light components from the probe beam produced "snapshots" of schlieren images showing the radial and axial evolution of the plasma. These images can be used to estimate the plasma's expansion velocity and electron density profile as a function of time.