Evaluation of a collisional radiative model for electron temperature determination in hydrogen plasma

A collisional-radiative (CR) model that extracts the electron temperature, T_e, of hydrogen plasmas from Balmer-line-ratio measurements is examined for the plasma electron density, n_e, and T_e ranges of 10¹⁰-10¹⁵ cm^-3 and 5-500 eV, respectively. The CR code, developed and implemented in Python, has a forward component that computes the densities of excited states up to n = 15 as functions of T_e, n_e, and the molecular-to-atomic neutral ratio r(H₂/H). The backward component provides n_e and r(H₂/H) as functions of the Balmer ratios to predict the T_e. The model assumes Maxwellian electrons. The density profiles of the electrons and of the molecular and atomic hydrogen neutrals are shown to be of great importance, as is the accuracy of the line-ratio measurement method.