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The observed power spectrum of high-degree solar p-modes (l>200) shows discrepancies with the power spectrum predicted by the stochastic excitement and damping theory. In an attempt to explain these discrepancies, the present paper is concerned with the influence of the observed subsurface flows on the trapped acoustic modes (p-modes). The effect of these inhomogeneous background flows is investigated by means of a non-modal analysis and a multi-layer model. It is shown that the rotational and meridional components of the velocity field change the wavelengths of the oscillation modes which, in turn, results in modifications of the corresponding modal frequencies. The magnitudes of the frequency residuals depend on the spatial scales of the modes and on the gradients of the different components of the flow velocity. Together with other mechanisms (e.g. the scattering of modes by the large scale convection (Goldreich & Murray 1994), the non-modal effect of the variation of the frequencies in time may contribute: 1) to the observed widening of the corresponding peaks in the observed power spectrum with increasing angular degree; 2) to the partial dissipation of spectral power, and, as a result, 3) to the discrepancies between the predicted and the observed power spectrum of solar p-modes.
The solar rotation profile is well constrained down to about 0.25 R thanks to the study of acoustic modes. Since the radius of the inner turning point of a resonant acoustic mode is inversely proportional to the ratio of its frequency to its degree,
Various models of solar subsurface stratification are tested in the global EULAG-MHD solver to simulate diverse regimes of near-surface convective transport. Sub- and superadiabacity are altered at the surface of the model ($ r > 0.95~R_{odot}$) to e
Turbulent motions in stellar convection zones generate acoustic energy, part of which is then supplied to normal modes of the star. Their amplitudes result from a balance between the efficiencies of excitation and damping processes in the convection
The pattern of migrating zonal flow bands associated with the solar cycle, known as the torsional oscillation, has been monitored with continuous global helioseismic observations by the Global Oscillations Network Group, together with those made by t
Several works have reported changes of the Suns subsurface stratification inferred from f-mode or p-mode observations. Recently a non-homologous variation of the subsurface layers with depth and time has been deduced from f-modes. Progress on this im