论文标题
从声学模式本征函数的扰动中推断太阳旋转
Inference of solar rotation from perturbations of acoustic mode eigenfunctions
论文作者
论文摘要
当今的内部太阳旋转速率曲线的图像基本上是由共振声波频率分布的热震分析所致。在这里，我们使用声波形状的扰动对内部太阳旋转速率进行了另一个互补估计。为此，我们扩展了以前开发的一种全球热震方法，用于研究子午流\ cite {schad11，schad12，schad13}，以处理差分旋转的组件。我们讨论旋转对模式本征函数及其基于可观察物的影响。基于使用模拟旋转速率曲线的数值研究，我们量身定制反转方法，还考虑存在额外的子午流量的情况。然后将这种反转方法应用于太阳辐射天文台（SOHO）仪器的MDI（Michelson多普勒成像仪）和HMI（Helioseissic和Helioseismic和磁成像仪太阳能动力学观测台（SDO））仪器的数据。最后，比较了根据本征函数扰动和频率分裂估计的旋转率曲线。 来自两种不同方法的旋转率曲线在定性上非常吻合，尤其是对于MDI数据。在高纬度$> 50^{\ circ} $和附近的地面上获得显着差异。 HMI数据的结果显示了不同方法之间的差异。我们发现，两种全球热震方法提供了测量太阳旋转的互补方法。比较不同方法的结果可能有助于揭示基于特征功能扰动（例如子午流量测量）的系统影响，这些影响会影响分析。
Today's picture of the internal solar rotation rate profile results essentially from helioseismic analyses of frequency splittings of resonant acoustic waves. Here we present another, complementary estimation of the internal solar rotation rate using the perturbation of the shape of the acoustic waves. For this purpose, we extend a global helioseismic approach developed previously for the investigation of the meridional flow \cite{schad11, schad12, schad13} to work on the components of the differential rotation. We discuss the effect of rotation on mode eigenfunctions and thereon based observables. Based on a numerical study using a simulated rotation rate profile we tailor an inversion approach and also consider the case of the presence of an additional meridional flow. This inversion approach is then applied to data from the MDI (Michelson Doppler Imager aboard the Solar Heliospheric Observatory (SoHO)) instrument and the HMI (Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory (SDO)) instrument. In the end, rotation rate profiles estimated from eigenfunction perturbation and frequency splittings are compared. The rotation rate profiles from the two different approaches are qualitatively in good agreement, especially for the MDI data. Significant differences are obtained at high latitudes $> 50^{\circ}$ and near the subsurface. The result from HMI data shows larger discrepancies between the different methods. We find that the two global helioseismic approaches provide complementary methods for measuring solar rotation. Comparing the results from different methods may help to reveal systematic influences that affect analyses based on eigenfunction perturbations, like meridional flow measurements.
