非径向模式的随机激励II。太阳的渐近重力模式是可探测的吗？
Stochastic excitation of nonradial modes II. Are solar asymptotic gravity modes detectable?
摘要：
探测太阳重力模式仍然是我们了解太阳内部的一个重大挑战。它们的频率将能够推导出对核心物理性质的约束，而它们的振幅可以对内对流区域的性质施加严格的约束。我们的目的是确定准确的理论振幅的太阳g模式和估计SOHO观测持续时间的一个明确的检测。我们调查的随机激励模式的湍流对流以及他们的阻尼。输入从一个三维全球模拟的太阳对流区的动能湍流能谱。阻尼计算使用的非本地时间依赖的对流脉动相互作用的参数化描述。然后，我们提供了一个理论估计的内在，以及表观，表面速度。渐近g-模式的速度振幅被发现的数量级高于以前的作品。使用3D数值模拟，从ASH代码中，我们将其归因于模式和湍流涡旋之间的时间相关性，发现其遵循洛伦兹定律而不是如先前使用的高斯定律。我们还发现，渐近重力模式的阻尼率占主导地位的辐射损失，与一个典型的寿命为$3 \times 10^5$年的$\ell=1$模式在$ν=60 μ$赫兹。在所考虑的频率范围（10-100 $μ$ Hz）内，获得了$\ell=1$模式在$ν=60 μ$ Hz和$\ell=2$在$ν=100 μ$ Hz的最大速度。由于建模中的不确定性，最大振幅，即60 $μ$ Hz下的$\ell=1$的振幅范围为3至6 mm s $^{-1}$。
英文摘要：
Detection of solar gravity modes remains a major challenge to our understanding of the innerparts of the Sun. Their frequencies would enable the derivation of constraints on the core physical properties while their amplitudes can put severe constraints on the properties of the inner convective region. Our purpose is to determine accurate theoretical amplitudes of solar g modes and estimate the SOHO observation duration for an unambiguous detection. We investigate the stochastic excitation of modes by turbulent convection as well as their damping. Input from a 3D global simulation of the solar convective zone is used for the kinetic turbulent energy spectrum. Damping is computed using a parametric description of the nonlocal time-dependent convection-pulsation interaction. We then provide a theoretical estimation of the intrinsic, as well as apparent, surface velocity. Asymptotic g-mode velocity amplitudes are found to be orders of magnitude higher than previous works. Using a 3D numerical simulation, from the ASH code, we attribute this to the temporal-correlation between the modes and the turbulent eddies which is found to follow a Lorentzian law rather than a Gaussian one as previously used. We also find that damping rates of asymptotic gravity modes are dominated by radiative losses, with a typical life-time of $3 \times 10^5$ years for the $\ell=1$ mode at $ν=60 μ$Hz. The maximum velocity in the considered frequency range (10-100 $μ$Hz) is obtained for the $\ell=1$ mode at $ν=60 μ$Hz and for the $\ell=2$ at $ν=100 μ$Hz. Due to uncertainties in the modeling, amplitudes at maximum i.e. for $\ell=1$ at 60 $μ$Hz can range from 3 to 6 mm s$^{-1}$.
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