This proposal on "Joint Observations of the Long Term Evolution of Solar Magnetic Fields" between Dr. Harold Zirin and Dr. Ken G. Libbrecht of California Institute of Technology and Professors Ai Guoxiang, Han Feng, and Liu Jianqiang of the Beijing Astronomical Observatory, is jointly sponsored by NSF and by the Chinese Academy of Sciences. At all times the sun is covered with weak magnetic fields arranged in the form of a network of elements 30 km across, thought to be generated by a large scale convective pattern. Attempts to measure the lifetime of the magnetic network have indicated that the elements last about 50 hours. What replaces them when they die out is not obvious. Unfortunately, studies from short daily runs provide good data for only 10 out of 24 hours, and do not show what the source of these moving elements might be. The investigators believe the only solution for this problem is to obtain continuous observations of these magnetic fields. At present, only the videomagnetographs of the Big Bear Solar Observatory and the Huairou Solar Observatory can perform this task. The program will use the combined capability of the two sites to cover 16 of 24 hours per day to follow the development and motion of the fields. By supplementing this with data from a patrol telescope in Tel Aviv, the investigators shall be able to follow the evolution of the small magnetic fields for several 24 hour periods and determine exactly how they evolve, thus achieving a new understanding of the magnetic features which underlie solar prominences.
