Some Questions and Challenges in Measurements of Solar Magnetic Fields

Huairou Solar Observing Station of the National Astronomical Observatories of the Chinese Academy of Sciences has been in operation since 1987. Successful observations of the solar vector magnetic field have been conducted during its operation. Based on the achievements at Huairou, we analyze the methods of observing the solar magnetic field, including discussions of the approximation of the transfer theory of the solar magnetic field in the atmosphere, wide field of view polarized observation, and some questions on the inversion of solar magnetic field data. We also present relevant challenges for further research.