论文标题
恒星和行星内部旋转对流的模型:ii-重力惯性波的产生
A model of rotating convection in stellar and planetary interiors: II -- gravito-inertial wave generation
论文作者
论文摘要
在对流和辐射区域的界面以及旋转恒星和行星对流区域中的雷诺应力上,引力惯性波被激发。这样的波在旋转恒星的频谱中具有显着的强震信号,尤其是在快速旋转的早期型恒星中,这提供了一种探测其内部结构和动力学的方法。它们还可以从激发区域传输角动量,化学物种和能量,到辐射区域消散的地方。为了估计这些波的振幅的激发和对流参数依赖性,如论文I所述,用于恒星和行星对流的单差模型,该模型被用作I中所述,这提供了RMS对流速度的大小作为旋转速率的函数。使用此对流模型,考虑了两个用于波动驱动的通道:在对流稳定和不稳定区域之间的边界上的激发以及由于雷诺压力而引起的激发。在亚惯性波可能带有明显的能量通量的情况下,发现参数状态,具体取决于对流的rossby数,界面刚度和波频率。超惯性波也可以增强,但仅用于对流的罗斯比数字接近统一的数字。当对流的流动数的流动数量低于关键的rossby数字时,界面激发的波在较低的截止频率附近具有峰值能量通量,该流量取决于界面的刚度,而当对流的rossby数量大于这个关键的rossby数字时,磁通量会降低。
Gravito-inertial waves are excited at the interface of convective and radiative regions and by the Reynolds stresses in the bulk of the convection zones of rotating stars and planets. Such waves have notable asteroseismic signatures in the frequency spectra of rotating stars, particularly among rapidly rotating early-type stars, which provides a means of probing their internal structure and dynamics. They can also transport angular momentum, chemical species, and energy from the excitation region to where they dissipate in radiative regions. To estimate the excitation and convective parameter dependence of the amplitude of those waves, a monomodal model for stellar and planetary convection as described in Paper I is employed, which provides the magnitude of the rms convective velocity as a function of rotation rate. With this convection model, two channels for wave driving are considered: excitation at a boundary between convectively stable and unstable regions and excitation due to Reynolds-stresses. Parameter regimes are found where the sub-inertial waves may carry a significant energy flux, depending upon the convective Rossby number, the interface stiffness, and the wave frequency. The super-inertial waves can also be enhanced, but only for convective Rossby numbers near unity. Interfacially excited waves have a peak energy flux near the lower cutoff frequency when the convective Rossby number of the flows that excite them are below a critical Rossby number that depends upon the stiffness of the interface, whereas that flux decreases when the convective Rossby number is larger than this critical Rossby number.