On the relationship between chromospheric oscillations of radio brightness at 1.76 cm with periods from minutes to hours and magnetic field changes

We present the results of Fourier and wavelet time series analysis for the high-cadence observations of an active region NOAA 8011, obtained with the Nobeyama Radioheliograph (NoRH) at the wavelength of 1.76 cm on 17.01.1997. Oscillations in brightness are found to be present with periods in the range from minutes to hours. The relationship between the active region oscillations in the microwave total intensity (I) and circular polarization (V) emission and changes of the magnetic field, deduced from the high-resolution magnetograms from MDI/SoHO, is investigated. We concentrate on the identification of different oscillation modes, the temporal behavior of the oscillations and the spatial distribution of different oscillating frequencies.