摘要: Many solar microwave bursts exhibit multicomponent spatial and spectral structure, which complicates efforts to determine source parameters from their radio emission. A small (SN/C1.0) flare that occurred on 1986 February 3 is dom... 展开 Many solar microwave bursts exhibit multicomponent spatial and spectral structure, which complicates efforts to determine source parameters from their radio emission. A small (SN/C1.0) flare that occurred on 1986 February 3 is dominated by a single, homogeneous source. High spectral resolution observations of this event with the Owens Valley frequency-agile interferometer therefore provide the clearest opportunity to date to apply theoretical spectral models to a microwave burst. Based on the microwave spectra, we find that the burst was dominated by a compact, thermal source. The sequence of such spectra, obtained every 10 s, showed that the source expanded with time during the burst, starting with a (one-dimensional) size of 4 arcsec, enlarging to about 12 arcsec in <2 minutes. During the same period, the electron temperature decreased from a high 71 million K to <10 million K. Comparison with GOES soft X-ray data suggests that the density increased by at least an order of magnitude during the burst. The magnetic field strength was found to be about 770 G. To apply these techniques to typical, more inhomogeneous flares, future observations are needed that achieve better imaging capability while retaining high spectral resolution. Keywords: Solar radio radiation; Solar X rays; Solar flares; Solar corona; Solar structure. (jhd) 收起