Abstract Chromospheric lines, including Hα, Lyα, Lyβ and CaII K, CaII 8542, are systemically and quantitatively investigated with respect to the non-thermal excitation and ionization due to particle beam bombardment for a series of solar semi-empirical atmospheric models. As a result we propose to use the contrast in the integrated intensity of hydrogen lines to estimate the total energy flux of the bombarding beam during the solar flare impulsive phase. Partial frequency redistribution is considered in the Lyα line calculation and a smaller intensity enhancement in the Hα line-centers is found than in the previous results of Fang et al.
Keywords Sun: flare --- Sun: chromosphere
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