Analysis of the solar magnesium I spectrum

Without assuming local thermodynamic equilibrium (LTE), we simultaneously solve the equations of statistical equilibrium and radiative transfer for a model Mg I atom that includes the lines 4571, 5172 (b2), and 2852 A, which we then compare with observations. From this comparison we determine by trial and error an optimum model of run with height of electron temperature, electron density, and total hydrogen density, and microturbulent velocity in the solar atmosphere up to approximately h = 1000 km. In addition, we show that the assumption of LTE for the 4571 A source function is valid to a high degree of precision.