Generation of laser-bullets-fast moving plasma blocks by interaction of intense laser pulse with plasma

Summary form only given. Generation of extremely stable light bullets in a preformed plasma near critical density has been observed experimentally. Optical probing measurements indicate the formation of a pulsating channels, typically of about 5 /spl mu/m in diameter, directed towards to a heating laser beam, as well as a disconnected massive plasma blocks moving also towards the laser beam. We report time-resolved results obtained by interferometric, absorption and Faraday rotation measurements for interaction of Nd:YAG laser beam at 1064 nm with a metallic target in air at an incident intensity of order of 1.4/spl times/10/sup 14/ W/cm/sup 2/. The formation of density ripples, cavitons in plasma channels, light bullets with self-generated magnetic field up to 4-7 MG, as well as their temporal evolution were investigated with high spatial and temporal resolution. The velocity of dense plasma blocks reaches values of order of 4.5/spl times/10/sup 8/ cm/s and they are stable during the acceleration and propagation in air. A figure represents a moving "laser-bullet" for probing time +60 ps.