Intensity of lines from low-lying levels in C ii, N iii, O iv, Ne vi, Mg viii, Si x, and Si ii

Abstract

The intensities of the lines for the transition ² P ^2/0₃ -² P ^2/0₁ in C ii, N iii, O iv, Ne vi, Mg viii, Si x, and Si ii in the chromosphere-corona transition region are investigated. The populations of the excited state ² P ^p0_f3/2 relative to the ground state ² P ⁰_f1/2 are obtained by considering all the radiative and collisional transition processes including the collisional transitions to the higher states which cascade to the upper level. It is found that in the transition region the intensity (which may be expressed as a function of temperature only) increases with the charge on the ion for a sequence.