No fluctuations in polarization have been found during a 7 GHz solar burst showing 17s periodic pulses in intensity. Polarization effects can be produced by the propagation media in the active centre, which are not affected directly by the burst source, but situated more deeply than the observed heights at that microwave frequency.
Kaufmann, P 
- Universidade Mackenzie, Sao Paulo (Brazil). Centro de Radio-Astronomia e Astrofisica