A Discussion on solar studies with special reference to space observations - Measurements of electron temperature in the solar chromosphere and corona

Abstract

The electron temperatures at which the lithium-like ions O vi, Nevm, and Mg x are formed in the solar chromosphere and corona were determined in a rocket experiment by measuring the intensity ratio of pairs of emission lines from the same ion. The ratios compared the intensity of the resonance multiplet 2s-2p with the multiplets 2s-3p, 2p-3s and 2p-3d. The theoretical dependence of the three ratios on electron temperature was determined by assuming that the free electrons have a Maxwellian distribution of velocities and that the electron distribution over the excited levels is given by a coronal-type equation. Collisional excitation cross-sections given by Bely and Burke et al. were used in the calculation. The experimental temperatures are in fairly good agreement with the theoretical temperatures of the maximum abundance of the ions obtained by assuming ionization balance.