论文标题
朝着与Ramses Code的恒星磁性转向进行完全可压缩的数值模拟
Toward fully compressible numerical simulations of stellar magneto-convection with the RAMSES code
论文作者
论文摘要
磁性转移的数值模拟大大扩展了我们对恒星内部和恒星磁性的理解。最近，全明星模型的完全可压缩的流体动力学模拟证明了研究恒星内饰中压力和内部重力波的激发和传播的可行性，这将与紫心学论测量直接进行比较。但是，在三维模拟中尚未考虑磁场对此类波的影响。我们进行了概念证明，以实现三维，完全可压缩的，磁性的磁动力学数值模拟，并使用Ramses代码对恒星内部的构图进行实现。我们通过在数值求解器中实现均衡的方案来调整RAMSES代码，以应对高度的湍流（典型的出色对流）。然后，我们运行并分析了三维流体动力学和磁动力学模拟，并在笛卡尔网格上使用平面平行的对流包膜分辨率不同。流体动力学和磁动力学模拟都从初始曲线上引入的随机密度扰动中形成了准稳态的湍流对流层。对流流的特征是恒星内部的流体动力平衡周围的振幅波动较小，在整个模拟时间内保存。使用我们可压缩良好的平衡方案，我们能够以低至$ \ MATHCAL {M} \ SIM 10^{ - 3} $低的MACH数进行建模，但原则上甚至可以使用较低的Mach数量流量。在磁流动力运行中，我们观察到与小规模发电机作用一致的磁能的指数生长。 （简略）
Numerical simulations of magneto-convection have greatly expanded our understanding of stellar interiors and stellar magnetism. Recently, fully compressible hydrodynamical simulations of full-star models have demonstrated the feasibility of studying the excitation and propagation of pressure and internal gravity waves in stellar interiors, which would allow for a direct comparison with asteroseismological measurements. However, the impact of magnetic fields on such waves has not been taken into account yet in three-dimensional simulations. We conduct a proof of concept for the realization of three-dimensional, fully compressible, magneto-hydrodynamical numerical simulations of stellar interiors with the RAMSES code. We adapted the RAMSES code to deal with highly subsonic turbulence, typical of stellar convection, by implementing a well-balanced scheme in the numerical solver. We then ran and analyzed three-dimensional hydrodynamical and magneto-hydrodynamical simulations with different resolutions of a plane-parallel convective envelope on a Cartesian grid. Both hydrodynamical and magneto-hydrodynamical simulations develop a quasi-steady, turbulent convection layer from random density perturbations introduced over the initial profiles. The convective flows are characterized by small-amplitude fluctuations around the hydrodynamical equilibrium of the stellar interior, which is preserved over the whole simulation time. Using our compressible well-balanced scheme, we were able to model flows with Mach numbers as low as $\mathcal{M} \sim 10^{-3}$, but even lower Mach number flows are possible in principle. In the magneto-hydrodynamical runs, we observe an exponential growth of magnetic energy consistent with the action of a small-scale dynamo. (Abridged)
