The Lyman-alpha/H-alpha ratio in solar flares and quasars

Constant temperature and density solar flare models are constructed with temperature and hydrogen density values that reflect reasonable nonlinear averages of those parameters in the depth dependent solar flare chromosphere models of Lites and Cook (1979). Acceptable values of the intensity ratios L-alpha/H-alpha and H-beta/H-alpha correspond to temperatures from about 9000 to 13,000 K, and hydrogen densities from 10 to the 11th to 10 to the 15th cu cm. The H-alpha and Ly-alpha source functions are thermalized at depths consistent with those inferred from independent studies, although the observed Ly-alpha/H-alpha ratio does not necessarily imply an electron temperature appropriate to the Planck function ratio. It is also shown that the value of Ly-alpha/H-alpha depends on the temperature, hydrogen density, and the optical depth of the emitting chromospheric layer.