Soft X-Ray Emission from Double-Electron Radiative Transitions in Plasma Ions

摘要

A broad emission blend is observed near 17 A from a plasma produced in a theta-pinch deuterium discharge seeded with neon. The feature is associated with KL to the nth power yields L to the (m+2) power + light where M > or = 6 double-electron radiative transitions resulting from the filling of a K-shell vacancy in the higher ionization species of the neon atoms by an L-shell electron, the simultaneous ionization (shake-off) or excitation (shake-up) of a second L-shell electron, and the emission of a photon. The observed spectral distribution of the blend is compared with the spectral distributions computed for various ion species by convoluting the instrument profile of the spectrograph with the predicted wavelengths and relative intensities of the shake-up lines and shake-off continua. A percentage probability for radiative- Auger shake-off in agreement with theory is derived from the Ne VIII portion of the measured spectrum. The possibilities of such transitions for enhanced plasma cooling and for gain by stimulated emission are mentioned. (Author)