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Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2010

Turbulent eddy-time-correlation in the solar convective zone

Résumé

Theoretical modeling of the driving processes of solar-like oscillations is a powerful way of understanding the properties of the convective zones of solar-type stars. In this framework, the description of the temporal correlation between turbulent eddies is an essential ingredient to model mode amplitudes. However, there is a debate between a Gaussian or Lorentzian description of the eddy-time correlation function (Samadi et al. 2003b, A&A, 403, 303; Chaplin et al. 2005, MNRAS, 360, 859). Indeed, a Gaussian description reproduces the low-frequency shape of the mode amplitude for the Sun, but is unsatisfactory from a theoretical point of view (Houdek 2010, Ap&SS, 328, 237) and leads to other disagreements with observations (Samadi et al. 2007, A&A, 463, 297). These are solved by using a Lorentzian description, but there the low-frequency shape of the solar observations is not correctly reproduced. We reconcile the two descriptions by adopting the sweeping approximation, which consists in assuming that the eddy-time-correlation function is dominated by the advection of eddies, in the inertial range, by energy-bearing eddies. Using a Lorentzian function together with a cut-off frequency derived from the sweeping assumption allows us to reproduce the low-frequency shape of the observations. This result also constitutes a validation of the sweeping assumption for highly turbulent flows as in the solar case.

Dates et versions

hal-03730837 , version 1 (20-07-2022)

Identifiants

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Kevin Belkacem, Davoud-Reza Samadi, Marie-José Goupil, Frederic Baudin, David Salabert, et al.. Turbulent eddy-time-correlation in the solar convective zone. Astronomy and Astrophysics - A&A, 2010, 522, pp.L2. ⟨10.1051/0004-6361/201015706⟩. ⟨hal-03730837⟩
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