VLA observations of the evolution of a solar burst source structure at 6 centimeter wavelength

Evolutionary changes in the total intensity and polarization structure of a 6 cm radio burst source have been observed with the VLA, over time scales ranging from 10 s to several minutes. This burst was associated with a 2B/M1 flare observed on 1980 May 14. The 6 cm burst consisted of a gradual phase of 30 minutes duration and a strong impulsive phase of duration less than two minutes. Synthesized maps of total intensity and polarization were obtained with spatial resolution of 2 x 3 arcsec and with temporal resolutions of five minutes during the gradual phase and 10 s during the impulsive phase. The sequence of polarization maps suggests a complex magnetic field structure undergoing rapid changes. Most importantly, they show the development of two bipolar regions or quadrupole structure just prior to the impulsive energy release.