Development of high resolution UV laser probing for 1-MA z-pinches

Laser probing diagnostics at the wavelength of 266 nm have been developed at the 1-MA pulsed power Zebra facility. Due to the smaller absorption and refraction at 266 nm, UV radiation penetrates deeper into the dense Z-pinch plasma. This allows the observation of fine details and structures of the Z-pinch plasma at the implosion and stagnation phases. UV interferograms and shadowgrams of the z-pinch plasma were compared to regular interferograms and shadowgrams at 532 nm. The UV laser shadowgraphy was shown to be a significant improvement in probing of wire array plasmas. Plasma distribution and dynamics in compact cylindrical, star, and planar wire arrays were studied at the wavelength of 266 nm. An electron density N_e > 5·10¹⁹ cm^-3 was measured directly in the stagnated Z-pinch with the 266nm differential interferometer. Two-color shadowgraphy shows low density "corona" plasma with the 532 nm laser and dense plasma structures with the 266 nm laser in wire arrays.