Polarized solar activity at mm-waves

The time development of active regions generates slow period variations in the solar flux, this is called the slowly varying component or S-component of radio emission. Thus, the study of structure and physical processes in active regions, estimation of plasma parameters referring to layer in solar atmosphere are accessible by radio methods [1]. Although the S-component is best known at centimeter wavelengths, their observations at millimeter wavelengths shall improve the understanding of the emission mechanisms involved in solar active regions. We show that emission from a quiescent solar active region observed by solar radio polarimeters at 45 and 90 GHz exhibits fluxes increasing with frequencies.