Hot Electron Generation by the Two-Plasmon Decay Instability in the Laser-Plasma Interaction at 10.6 μm

Hot electron generation in a long-density-scale-length (∼300 μm) underdense plasma has been studied. For a plasma of maximum electron density of $\frac{1}{4}{n}_c$ the hot electron emission is localized in the plane of polarization of the incident C${\mathrm{O}}_2$ laser and peaked about 45° with respect to the $\overrightarrow{\mathrm{k}}$ vector of the laser beam, in both forward and backward directions. These observations suggest that the hot electrons are generated by the two-plasmon decay instability at quarter-critical density.