Radiative power and electron cooling rates for oxygen in steady-state and transient plasmas at densities beyond the coronal limit.

Abstract

We have developed a time-dependent, collisional-radiative model to calculate radiative power and electron cooling rates for oxygen at intermediate densities (${10}^{16}$\ensuremath{\le}${n}_{e}$\ensuremath{\le}${10}^{20}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$) where the usual coronal approximation is not valid. Large differences from coronal values are predicted. The behavior of the steady-state radiative-power-loss coefficient, ${L}_{z}$, is investigated as the electron density is increased. Generalized power-loss coefficients applicable to transient plasmas are derived and applied to ionizing and recombining oxygen plasmas. Time-dependent effects are found to play a large role both in terms of the total radiated power and the net electron-energy-loss rate.