The polarization of solar radio emission at 74 MHz: May 18–26, 1967

The passage of McMath plage region 8818 over the visible solar disk resulted in extensive meter-wavelength activity of spectral types I, II, III and IV. The activity at 74 MHz and its polarization have been observed with a narrow-band (10 kHz) timesharing radio polarimeter. Newly adopted data recording and processing techniques have enabled time-histories of the polarization characteristics of the solar emission to be obtained with a time resolution of 1/4 second. The polarization patterns for all the major activity in the May 18–26 period are described. They exhibit considerable variety in the degree and ellipticity of the polarization observed during both short-lived bursts and long-enduring periods of activity. Both simple and complex patterns were seen when changes in the sense of polarization of the solar emission occurred. Methods used to determine the polarization characteristics of the solar emission in the presence of galactic emission and to resolve the complexities of the solar emission itself are illustrated.