Time-resolved extreme-ultraviolet emission from sixteen 3p-3s transitions, some of the type in which lasing has been demonstrated in heavire elements, is measured for neonlike ${\mathrm{Ar}}^{8+}$ and ${\mathrm{Cl}}^{7+}$. These observations are made on a hydrogen θ-pinch plasma with a 5% admixture of argon or freon (for Cl). Fourteen 3d-3p spectral lines are also detected. The measured intensities are compared to theoretical predictions. All major lines agree within ±30%. Hence, there is no evidence of anomalously intense lines originating on 2$p^5$3p J=2 upper levels compared to J=0, as observed in gain experiments.

• Received 17 April 1989

DOI:https://doi.org/10.1103/PhysRevA.40.4142