Recombining plasma X-ray laser assisted by charge exchange recombination

Recombining plasma x-ray laser using charge exchange recombination (CXR) is proposed. Fully stripped carbon ions collide with neutral He atoms and bec ome excited hydogenlike carbon ions, in which the excited levels with n = 3 or 4 are mainly populated. We calculated the gain coefficients of the Balm er alpha and Lyman beta lines of the hydrogenlike carbon ions by the use of a collisional-radiative model in which the CXR proms is included. The calc ulated result shows that substantial gain can be generated for the Lyman be ta and Balmer alpha lines and that the gain of the Balmer alpha line can be strongly enhanced by the effect of CXR. We also report a preliminary exper iment of this scheme.