GONG p-Mode Parameters Through Two Solar Cycles

We investigate the parameters of global solar p-mode oscillations, namely damping width $$ , amplitude $$ , mean squared velocity $$ , energy $$ , and energy supply rate $$ , derived from two solar cycles' worth (1996 - 2018) of Global Oscillation Network Group (GONG) time series for harmonic degrees $$ . We correct for the effect of fill factor, apparent solar radius, and spurious jumps in the mode amplitudes. We find that the amplitude of the activity-related changes of $$ and $$ depends on both frequency and harmonic degree of the modes, with the largest variations of $$ for modes with $$ and $$ with a minimum-to-maximum variation of $$ and of $$ for modes with $$ and $$ with a minimum-to-maximum variation of $$ . The level of correlation between the solar radio flux $$ and mode parameters also depends on mode frequency and harmonic degree. As a function of mode frequency, the mode amplitudes are found to follow an asymmetric Voigt profile with $$ . From the mode parameters, we calculate physical mode quantities and average them over specific mode frequency ranges. In this way, we find that the mean squared velocities $$ and energies $$ of p modes are anticorrelated with the level of activity, varying by $$ and $$ , respectively, and that the mode energy supply rates show no significant correlation with activity. With this study we expand previously published results on the temporal variation of solar p-mode parameters. Our results will be helpful to future studies of the excitation and damping of p modes, i.e., the interplay between convection, magnetic field, and resonant acoustic oscillations.