Short-wavelength laser calculations for electron pumping in carbonlike and heliumlike ions

A steady-state computer code has been used to compute population densities of excited terms in carbonlike and heliumlike ions. It is shown that an inversion between terms of the 1s22s22p3p and 1s22s22p3s configurations sufficient to produce observable laser gain can be obtained in high-density plasmas such as produced by laser irradiation of pellets or electromagnetically driven pinch discharges. Such inversions in elements of atomic number Z = 15–40 give rise to lasing in the 300–1200 Å range. Shorter wavelength lasing (5–80 Å) on 1s3s→1s2p transitions in heliumlike ions of Z = 10–40 is also modeled, but significant gain is probably not possible with current plasma devices.