X-pinch plasma as an optical pumping source for x-ray lasers

A high-transmission spectrograph equipped with a spherical mica crystal was used to study x-ray emission from an X-pinch plasma at high spectral (λ/Δλ ~ 3000) and spatial (~30 μm) resolutions. H- and He-like spectra of Al and Si ions generated in the X-pinch were detected both in the stage of maximum compression and in the dispersal stage. The electron temperature (up to 950 eV) and density (up to 2 · 10²⁴ cm^–3 ) of the plasma at the "hot point" and also in the dispersal stage were measured by x-ray spectral methods. Energy estimates show that the radiation output in the K lines can reach 1 J (the corresponding power is 1 GW). The overall energy radiated in the wavelength region 0.5 to 10 nm is ~1 kJ. This result indicates that the radiation from the "hot point" of an X-pinch plasma can be an effective pumping source for the active medium of an x-ray laser. It also indicates that the recombining plasma dispersing out of the hot region can itself be used as an active medium for short-wavelength lasers.