High-Gain Recombination O-Viii X-Ray Laser

A scheme is presented for producing a high gain recombination x-ray laser in hydrogen like oxygen by irradiating 7-mum-diam fiber targets with picosecond high-power laser pulses. The lasing gain coefficient for the O VIII Balmer a transition at 10.2 nm is predicted to be over 100 cm-1. The optimized electron density and temperature are 8.8 X 10(19) cm-3 and 22 eV, respectively, at the time when the lasing gain reaches its maximum. Significant improvement in gain performance of recombination x-ray lasers is indicated for picosecond pulse drivers, which might be a route towards saturated recombination x-ray layers.