Diagnoses of the Stratif ication of Vector Magnetic fields in the Solar Atmosphere

In the thesis, the application of the line formation depth theory to diagnose the vector magnetic field stratification in solar atmosphere is examined. The advantages as well as disadvantages of the methods concerning the cont ribution function and response function are pointed out respectively. Then the influence of the gradients of the profile parameters on the profiles themselves, especially their symmetry as well as the extremum points are inrestig ated. After this, the basic assumption is presented and it simplies greatly the polarized radiative transfer equations at the extremum points. Thus a new method is proposde, which is independent of the line formation depth theory, and consists of four operations. When three of the four operations are executed cyclically, the strat if ication of the profile parameters are obtained and the profiles under the surface are computed out. The diag noses is operated down step by step, and the resulted parameters, especially the st rength of the magnetic field, are satisfactory. When fitting the synthetic and observed profiles, it is found that the fitting profiles and the fitted coincide well in the wavelength region where the method uses, and even the complicated structure of the magnetic fields can be extracted. But the method suffers from several problems, which include that the inferred depth region is narrow and the‘surface’ to which the inferred parameters are ascribed to can not be accurately determined.