The possibility of a capillary discharge soft X-ray laser with shorter wavelength by utilizing a recombination scheme

The capillary discharge soft X-ray laser is a promising scheme with its long capillary plasma column that is efficiently generated by the fast current pulse of about several 10s ns. In this study, the possibility of a recombination soft X-ray laser will be discussed in anticipation of realizing a 13.4 nm H-like N EUV laser. Evolution of EUV emission from nitrogen plasma with number density of 10cm was measured and analyzed with MHD calculation. Comparing the experimental and the calculation results, it is considered that in order to initiate the collisional ionization effectively in a few ns and to obtain many fully-stripped nitrogen ions enough for lasing, much higher electron number density is required. The possibility of realizing a recombination soft X-ray laser pumped by the capillary discharge is discussed.