Improvement of the inversion accuracy of the Ca II line profiles using response functions

The line profile inversion is as a rule used to model the atmosphere. The algorithm for determining the temperature and electron density in the middle chromosphere has been developed based on inversion of the profiles of five Ca II chromospheric lines. Necessary information is contained in the function called by us the population function. This function is used to calculate the frequency-dependent source functions in lines and, consequently, the rates of radiative transitions. However, the accuracy of population function reconstruction in the inversion procedure is insufficient for the goal to be achieved. The accuracy is increased by using the intensity response function conception. The response functions of five Ca II lines to the population function disturbances have been calculated. The accuracy to be achieved has been estimated using one of the semiempirical models of the sunspot umbra as an example.