Amplitudes of Solar Gravity Modes: A Review

Solar gravity modes are considered the Rosetta Stone for probing and subsequently deciphering the physical properties of the solar inner-most layers. Recent claims of positive detection therefore shed some new light on the long-standing issue of estimating solar gravity mode amplitudes. In this article, our objective is to review the theoretical efforts intended to predict solar gravity-mode amplitudes. Because most of these studies assume analogous driving and damping properties to those of the observed acoustic modes, we also provide a short overview of our current knowledge for these modes in the Sun and solar-type stars (which show solar-like oscillations) before diving into the specific problem of solar gravity modes. Finally, taking recent estimates into account, we conclude and confirm that the low-frequency domain (typically between 10 and 100 ) is certainly best suited to focus on for detecting solar gravity modes. More precisely, around 60 (approximately four-hour period), the theoretical estimates are only slightly lower than the observational detection threshold as provided by the GOLF ( Global Oscillations at Low Frequencies ) instrument by about a factor of two. This is typically within the current uncertainties associated with theoretical estimates and should motivate us to improve our knowledge on turbulence in the whole solar convective region, which is key to improving the accuracy of g -mode amplitude estimates. The recent detection of solar inertial modes (Gizon et al., Astron. Astrophys. 652 , L6, 2021 ) combined with the continuous development of numerical simulations provide interesting prospects for future studies.