Local Helioseismology with GONG

全球振荡网络小组（GONG）最近进行了升级，包括更高分辨率的CCD相机，这是一个以社区为基础的方案，利用日震学对太阳的结构和动力学进行详细研究。我们现在所称的全球日震学对于确定太阳的径向结构，以及轴对称流的深度和纬度变化，如旋转和扭转振荡，都是非常宝贵的。 然而，全球模式的频率是相对不敏感的方位角变化的结构，北/南半球的不对称性，小规模的流动，和纬向流。近年来，人们采用了新的诊断方法，从局部而不是全球的角度来探索太阳内部。研究人员正在开发计算地震全息术，作为一种有效和通用的工具，旨在对太阳内部进行成像，以达到波衍射所允许的最佳空间分辨率。他们正在将相敏地震全息术应用于跨越半个太阳周期的GONG观测，以研究太阳对流区大部分地区的流动和声速扰动的短期和长期时间特性。 他们将探索赤道环流的地下性质，其他地下流动的性质及其与磁活动的联系，以及速跃层和太阳极的局部声学特性。更广泛的影响：该项目正在增加我们对太阳周期的理解，从而提高我们的预测能力。这对于太空探索、地球传感、天气预报和通信至关重要，这些都受到太阳活动的影响。

The Global Oscillation Network Group (GONG), recently upgraded to include higher resolution CCD cameras, is a community-based program to conduct a detailed study of the structure and dynamics of the Sun using helioseismology. What we now call global helioseismology has been invaluable for determining the radial structure of the Sun, as well as the depth and latitude variation of axisymmetric flows, such as rotation and torsional oscillations. However, global-mode frequencies are relatively insensitive to azimuthally varying structure, north/south hemispheric asymmetries, small-scale flows, and meridional flows. New diagnostics have been employed in recent years to explore the solar interior from a local rather than a global perspective. The investigators are developing computational seismic holography as an efficient and versatile tool designed to image the solar interior to the optimum spatial resolution permitted by wave diffraction. They are applying phase-sensitive seismic holography to GONG observations, spanning half a solar cycle, to study the short-term and long-term temporal properties of flows and sound-speed perturbations throughout much of the solar convection zone. They will explore the subsurface nature of meridional circulation, the nature of other subsurface flows and their connection with magnetic activity, and the local acoustic properties of the tachocline and the solar poles. Broader impacts: The project is increasing our understanding, and hence our predictive capability, of the solar cycle. This is essential for space exploration, earth sensing, weather forecasting, and communications that are all impacted by solar activity.