Long period global quiet coronal oscillations

We Fourier analyzed the unevenly spaced data of globally averaged radio fluxes (at 275, 405, 670, 810, 925, 1080, 1215, 1350, 1620 and 1755 MHz) and preliminary results are presented in this poster. We find following dominant periodicities whose powers are greater than 4sigma level : (i) 274 and 110 day periodicities for all the flux values, (ii) 25 day in the 1755, 1620, 1350, 1215, 1080, 925, 810,670 flux values (iii) 26.1 and 19.6 day periodicities in the 275 and 65 flux values and, (v) 23 and 14.8 day periodicities in the 275 MHz flux value only. In order to confirm the osillatory nature of these waves, we compute phases of 25 day, 110 day and 274 day periodicities with respect to their different radio frequencies (altitudes) and find that their phases remain constant for the flux values 1755 MHz (originating approximately at the altitude of 70,000 Km) to 670 MHz (originating approximately at the altitude of 1,30,00 Km) suggesting standing oscillations in this region of the corona. However, phases of these periodicities are not constant for the 405 MHz and 275 MHz flux values.