The structure of K_α and K_β lines radiated from highly ionised plasmas

The K_alpha and K_beta radiation from Fe, Ni and Ti plasmas in a low inductive spark has been investigated both experimentally and theoretically. A high-dispersion and high-resolution Johann crystal spectrograph has been used for the measurements. The theoretical analysis is based on relativistic perturbation theory with a zero-order model approximation. Some K_alpha and K_beta spectra features are qualitatively explained and some K_beta lines are identified for the first time. It has been shown that the observed time and space integrated spectrum is due mainly to the low M-shell ions. The calculation shows that this qualitatively explains the long-wavelength K_alpha plasma radiation shift relative to the solid state K_alpha line. The K_alpha radiation from high ions would be shifted to the opposite side.