Laser-Irradiated Gas Puff Target Plasma Modeling

Gas puff laser plasma is studied as a water window radiation source. The emitted radiation at 2.88-nm wavelength, corresponding to the transition 1s²-1s2p of helium -like nitrogen ion, is evaluated. Spatial development of plasma created by Nd:YAG laser beam focused on nitrogen jet was simulated by code Z*. The gas stream was approximated by a layer of thickness equal to the gas stream diameter at the position of laser beam passage. Results for 0.72-mm nitrogen gas layer and 7-ns FWHM laser pulse with energy of 600 mJ are presented.