A study is made of the differences in the polarization distribution and other characteristics of microwave emission for several active regionswith high flare productivity. Conclusions are drawn about the magnetic fiel...A study is made of the differences in the polarization distribution and other characteristics of microwave emission for several active regionswith high flare productivity. Conclusions are drawn about the magnetic field structure of these regions at coronal heights.展开更多
Input data of the system are two-dimensional images and one-dimensional distributions of total and polarized solar emission at 5.2 cm wavelength obtained with SSRT. Together with photoheliograms, magnetograms, Hα-fil...Input data of the system are two-dimensional images and one-dimensional distributions of total and polarized solar emission at 5.2 cm wavelength obtained with SSRT. Together with photoheliograms, magnetograms, Hα-filtergrams and characteristics of active regions received from other sources, they form the initial database. The first stage includes superimposing the images, identifying microwave sources with active regions, assigning NOAA numbers to the sources, and determining for each active region the heliolatitude, extent, and inclination angle of the group's axis to the equator. These data are used to calculate the boundaries of longitude zones for each active region. A next stage involves determining the brightness temperatures of microwave sources less than the polarization distribution, the degree of polarization, and microwave emission flux, as well as calculating the parameters of microwave sources. Each parameter is assigned its own value of the weight factor, and the sum of values is used to draw the conclusion about the flare occurrence probability in each active region and on the Sun in general.展开更多
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 Ministry of Industry and Science (No.477.2003,2)Russian Federal Program "Astronomy", and the China- Russia Joint Research Center on Space WeatheChinese Academy of Sciences
文摘A study is made of the differences in the polarization distribution and other characteristics of microwave emission for several active regionswith high flare productivity. Conclusions are drawn about the magnetic field structure of these regions at coronal heights.
基金Supported by the Education and Science Ministry of Russian Federation (477.2003.2)Russian Federal Program "Astronomy"the China-Russia Joint Research Center on Space Weather, Chinese Academy of Sciences
文摘Input data of the system are two-dimensional images and one-dimensional distributions of total and polarized solar emission at 5.2 cm wavelength obtained with SSRT. Together with photoheliograms, magnetograms, Hα-filtergrams and characteristics of active regions received from other sources, they form the initial database. The first stage includes superimposing the images, identifying microwave sources with active regions, assigning NOAA numbers to the sources, and determining for each active region the heliolatitude, extent, and inclination angle of the group's axis to the equator. These data are used to calculate the boundaries of longitude zones for each active region. A next stage involves determining the brightness temperatures of microwave sources less than the polarization distribution, the degree of polarization, and microwave emission flux, as well as calculating the parameters of microwave sources. Each parameter is assigned its own value of the weight factor, and the sum of values is used to draw the conclusion about the flare occurrence probability in each active region and on the Sun in general.
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.
