The transition region between the photosphere and the chromosphere under solar flares

Consideration is given to possible mechanisms for the greater depth and temperature of the transition layer from the photosphere to the chromosphere under solar flares with respect to quiet regions. It is shown that although an increase in the energy flux to the surface may account for an increase in the depth and temperature of the temperature minimum marking the photosphere-chromosphere transition, in the case of solar flares a change in the ionization equilibrium may lead to corresponding changes in the emission mechanism leading to the observed changes in the depth and temperature of the transition layer