Chromospheric backradiation in ultraviolet continua and Hα

A recent paper states that ultraviolet backradiation from the solar transition region and upper chromosphere strongly affects the degree of ionization of minority stages at the top of the photosphere, i.e., in the temperature minimum of the one-dimensional static model atmospheres presented in that paper. We show that this claim is incompatible with observations and we demonstrate that the pertinent ionization balances are instead dominated by outward photospheric radiation, as in older static models. We then analyze the formation of Hα in the above model and show that it has significant backradiation across the opacity gap by which Hα differs from other strong scatttering lines.