Radio Signature of Coronal Magnetic Field and Reconnection

A series of recent works using the radio spectrometer(with high time and frequency resolutions) and Nobeyama Radio Heliograph(with high spatial resolution) for analysis coronal magnetic field and reconnection are summarized in this paper.The main conclusions include:1) Under the approximations of Dulk et al(1982),the parallel and perpendicular components of the magnetic field in the sources of radio bursts are calculated self-consistently,and 2-dimensional distribution was obtained firstly.2) To consider the effect of low-cutoff energy of non-thermal electrons,it is necessary to calculate with more strict theory of gyro-synchrotron radiation.It is shown that the low-cutoff energy has evident effect on the calculations,but the effects of the other parameters(such as the ambient temperature and density,high-cutoff energy,and emission direction) may be neglected.Therfore the low-cutoff energy and coronal magnetic field should be solved together.3) The fine structures in radio bursts may show that the sources of the radio bursts are located close to the particle acceleration(magnetic reconnection) sites.It is possible to fix the locations of the sources of the fine structures,as well as the exact location and time of the particle acceleration(magnetic reconnection) using the radio spectrometer with high time and frequency resolutions and radio heliograph with high spatial resolution.These works are concentrated in the recent key points of solar physics,and will be developed further.