Electron-impact ionization-rate coefficients for lithiumlike nitrogen and oxygen

Abstract

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 $N_e\approx 4\times {10}^{15}$ ${\mathrm{cm}}^{-3\mathrm{}}$ and $k{T}_e\approx 80$ eV during the time of principal interest. Under these conditions, the ionization-rate coefficient for lithiumlike nitrogen is (7.4±2.2)×${10}^{-10\mathrm{}}$ ${\mathrm{cm}}^3$ ${\mathrm{s}}^{-1\mathrm{}}$, and that for lithiumlike oxygen is (4.1±1.2)×${10}^{-10\mathrm{}}$ ${\mathrm{cm}}^3$ ${\mathrm{s}}^{-1\mathrm{}}$. 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.