Linear correlations between peak frequency of gyrosynchrotron spectrum and photosphere magnetic fields

Abstract

The gyrosynchrotron spectra are computed in a nonuniform magnetic field case, taking into account the self- and gyroresonance absorption. It is found that the peak frequency nu(p) of the gyrosynchrotron spectrum systematically increases with the increasing photosphere magnetic field strength B-0 and increasing viewing angle theta. It is also found for the first time that there are good positive linear correlations between nu(p) and B-0, and between log nu(p) and log theta, with linear correlation coefficient 0.99 between nu(p) and B-0 and 0.95 between log nu(p) and log theta. We apply the correlations to analyze two burst events observed with OVSA and find that the evolution tendencies of the photosphere magnetic field strength B-0 estimated from the above expression are comparable with the observational results of SOHO/MDI. We also give a comparison of the diagnostic results of coronal magnetic field strength in both uniform and nonuniform source models.