Long-Scale Jet Formation with Specularly Reflected Light in Ultraintense Laser-Plasma Interactions

Long-scale jetlike x-ray emission was observed in a 100-TW laser-plasma interaction. The jet was well collimated with a divergence of 30–40 mrad and continued from the target surface into underdense regions for a distance over 4 mm in the specular direction of the laser light. A two-dimensional particle-in-cell simulation shows an electron acceleration with the specularly reflected laser light and collimation of the electron stream by a self-generated magnetic field, resulting in the electron jet to the direction of the specularly reflected light.