Ultra-high-intensity laser propagation through underdense plasma

Picosecond resolution shadowgraphy is a powerful tool for measurement of high-intensity laser propagation instabilities through underdense plasma. It is shown that as the plasma density increases, the laser beam is subject to severe filamentation instabilities-likely due to the effect of stimulated Raman side-scattering. At higher plasma densities, scattering and absorption are so severe that the propagation distance of the high intensity laser pulse is reduced.