Self-Focusing of 10.6-μm Radiation in an Underdense Plasma

Abstract
Self-focusing filaments have been observed in a long-scale-length plasma irradiated with a 10.6-μm beam containing hot spots. Filaments were observed by use of Thomson scattering from electron plasma waves produced by two-plasmon decay in the walls of the filament, and Fresnel reflection of a visible probe beam from the density discontinuity at the filament boundary.