Determination of plasma electron densities from the intensity ratio of resonance and intercombination lines of helium-like ions

The electron density was measured in a thin layer of magnesium laser plasma, positioned along the axis of a jet at its center. In this way, the effect of the optical thickness on the resonance line emission of a helium-like Mg xI line was eliminated, the contribution of the outer regions of the jet to the emission of this line being considerably weakened. Agreement was achieved, for the first time under these experimental conditions, between the electron density profile determined from the intensity ratio of the resonance and intercombination lines of a helium-like ion and that deduced from Stark broadening of the lines of a hydrogen-like ion.