Soft-x-ray laser scheme in a plasma created by optical-field-induced ionization of nitrogen

An x-ray laser scheme based on the recombination of a fully stripped nitrogen plasma is presented. Plasma is assumed to be created by the optical-field ionization of a nitrogen gas jet of 10(19) cm-3 atomic density by an ultrashort (60 fs), high-intensity (3 x 10(19) W/cm2) Ti:sapphire laser. Results of two-dimensional particle-in-cell simulations, modeling laser-plasma interaction, parametric heating, and ponderomotive effects are presented. Hydrodynamic and kinetics calculations are performed and predict important local gain for H-like nitrogen transitions at 25 and 134 A, following fast collisional recombination for specific plasma conditions.