An Analytical Method of the Spectra of the Active Bodies with the Three-Layer Radiative Structure on the Solar Disk and at the Solar Limb

Analyses of the solar spectra are usually used to study the solar active plenomena. In recent several decades, a lot of analytical methods for a single solar active feature have been proposed. In this paper the author reports on the following pieces of work:(Ⅰ) All the analytical methods of the solar spectral lines given from China in the recent decade are briefly presented,(Ⅱ) The formula for the line profile of the active bodies with the two-layer radiative structur is given,(Ⅲ) The analytical method of the spectra of the active bodies with the three-layer rediative structure is also given,(Ⅳ) The three analytical methods are compared with one another and(Ⅴ) As an example of the three-layer model, two Ha lines of the flare of 1989 August 17, are fitted.