Coronal Hole Oscillations as inferred from SDO/AIA data

With high temporal resolution (12 s) of about two hours duration, data of a coronal hole structure in 171 Å, 193 Å and 211 Å taken from SDO/AIA images is considered for examination of oscillations. After estimating the total DN counts of a whole coronal hole structure in three wavelength bands, the resulting time series are subjected to FFT and wavelet analysis. Significant periods in all the three wavelength bands are detected that are mainly concentrated around 500 s as a fundamental mode and its odd (167, 100, 71, 56, 46, 39, 33, 29, 26, 24 s) harmonics. Computed phases in all the three wavelengths band are estimated to be constant.