Measurement Of Solar Vector Magnetic Fields And Research On The Fields

Magnetic field plays a central role in solar activity. And the evident representation of solar magnetic atmosphere is these sunspots. So to research the properties of sunspots is an important field. Now we have learn about some basic properties of sunspots by observing and studying them. We have summarized the process of the measurement of the solar vector magnetic fields and research on them. The basic physical principle of measuring magnetic fields, the establishment of the polarized radiative transfer equation, the solutions of the polarized radiative transfer equation and the inversion code of the magnetic fields are the main parts of this process. We present the results of our work on the measurements of magnetic fields of sunspots. The main contents are as following:Since sunspots were the first astronomical objects recognized to harbour a magnetic field by Hale(1908), we have learned many characters of the structures of sunspots magnetic fields. The reliable stratification of vector magnetic fields of sunspots began with the work of Westendorp Plaza et al. (2001) by full Stokes profiles analysis using their code SIR. Here we present a two-slab atmosphere model. In each slab there are 9 parameters(vector magnetic fields,velocity fields and so on).Our inversion method that measures the magnetic fields adopts the numerical DELO solution to the polarized radiative transfer equation. Through the systemic tests with the theoretic profiles, we have obtained the errors of this method. The inversion method can recover the vector magnetic field with errors within 80G for field strength, 6° for field inclination and 8° for field azimuth.We have derived the optical stratification of vector magnetic fields of a 8 sunspot using our inversion technique and briefly discussed some features of this region. The stratification shows, as expected, that for this 8 sunspot, its stratification of the vectormagnetic fields has the main features of this kind: one umbra with positive polarity and the other with negative polarity; and the magnetic field vectors in the penumbra part between the two umbrae are more horizontal than those in the umbrae. On the other hand, comparing the zeniths of vectors in.the two umbrae, these in the upper layers are more vertical than those in lower layers on average. This indicates that the magnetic loops connecting the two umbrae are more spread upwards. At last, we have found that the neutral line is more complicatedly and widely spread on the lower slab than that on the upper one.