ELECTRON-IMPACT IONIZATION-RATE COEFFICIENTS FOR LITHIUM-LIKE NITROGEN AND OXYGEN

The electron-impact ionization-rate coefficients for lithiumlike nitrogen and oxygen are obtained from the time evolution of spectral lines emitted by a hot plasma. The plasma is produced in a 37-kJ theta pinch. Laser scattering diagnostics indicate that Ne 4×1015 cm-3 and kTe 80 eV during the time of principal interest. Under these conditions, the ionization-rate coefficient for lithiumlike nitrogen is (7.4 2.2)×10-10 cm3 s-1, and that for lithiumlike oxygen is (4.1 1.2)×10-10 cm3 s-1. The rate coefficients measured here and all other measurements of lithiumlike ionization rate coefficients are compared to calculations of the ground-state ionization-rate coefficient and the total-ionization-rate coefficient. © 1978 The American Physical Society.