Magnetic fields and solar activities (Q863239)

The study of solar magnetic fields based on the photospheric vector magnetograms of solar activity regions which were obtained at Huairou Solar Observing Station near Beijing in the period of the 22nd and 23rd solar activity cycles are discussed. Especially the measurements of the chromospheric magnetic field and the spatial configuration of the field at the lower solar atmosphere are inferred from both the distributions of the solar photospheric and chromospheric magnetic fields. To make conclusions about the accuracy of the magnetograms Huairou data are compared with MSFC data. Analysing the formation process of the delta configuration of the magnetic field in some superactive regions based on the photospheric vector magnetogram observations, the following results are obtained: (1) The analysis of the magnetic writhe of the whole active regions cannot be limited to the strong field of sunspots, because the contribution of the fraction of decayed magnetic field is non-negligible. (2) The magnetic model of kink magnetic flux ropes, proposed to be generated in the subatmosphere, is not consistent with the evolution of large-scale twisted photospheric transverse magnetic fields and with the magnetic shear in some delta active regions. (3) The proposition is that the large-scale delta active regions are formed by highly sheared non-potential magnetic flux bundles generated in the subatmosphere. Results of a study of the magnetic helicity are presented. These results are compared with other data sets obtained by magnetographs (or Stokes polarimeters) at different observatories, and the basic chirality of the magnetic field in the solar atmosphere is analysed.