Visualization of the Nonlinear Laser-Plasma Expansion

The high-power iodine laser PALS is used to study nonlinear processes in a laser-produced plasma. Longitudinal structures of the expanding plasma, recorded by using an X-ray streak camera on a time scale ~ 2 ns, are presented. Various bright spots, expansion-path curvature, and even their splitting are shown. These phenomena are ascribed to the effect of magnetic field, self-generated at high laser intensities.