We have performed microwave diagnostics of the magnetic field strengths in solar flaring loops based on the theory of gyrosynchrotron emission.From Nobeyama Radioheliograph observations of three flare events at 17 and...We have performed microwave diagnostics of the magnetic field strengths in solar flaring loops based on the theory of gyrosynchrotron emission.From Nobeyama Radioheliograph observations of three flare events at 17 and 34 GHz,we obtained the degree of circular polarization and the spectral index of microwave flux density,which were then used to map the magnetic field strengths in post-flare loops.Our results show that the magnetic field strength typically decreases from ~800 G near the loop footpoints to~100 G at a height of 10-25 Mm.Comparison of our results with magnetic field modeling using a flux rope insertion method is also discussed.Our study demonstrates the potential of microwave imaging observations,even at only two frequencies,in diagnosing the coronal magnetic field of flaring regions.展开更多
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDA17040507)the National Natural Science Foundation of China (Grant Nos. 11790300, 11790301, 11790302, 11790304, 11825301, 11973057, 11803002 and 11473071)。
文摘We have performed microwave diagnostics of the magnetic field strengths in solar flaring loops based on the theory of gyrosynchrotron emission.From Nobeyama Radioheliograph observations of three flare events at 17 and 34 GHz,we obtained the degree of circular polarization and the spectral index of microwave flux density,which were then used to map the magnetic field strengths in post-flare loops.Our results show that the magnetic field strength typically decreases from ~800 G near the loop footpoints to~100 G at a height of 10-25 Mm.Comparison of our results with magnetic field modeling using a flux rope insertion method is also discussed.Our study demonstrates the potential of microwave imaging observations,even at only two frequencies,in diagnosing the coronal magnetic field of flaring regions.
