测试流动走时灵敏度核的体积分
Testing volume integrals of travel-time sensitivity kernels for flows
AI总结：
通过操纵跟踪速率模拟纬向速度并测量东西向走时依赖关系，测试了日震学灵敏度核的体积分，发现ridge filtering数据一致性良好，而phase-speed filtered数据存在差异。
摘要：
背景：日震学反演在很大程度上依赖于灵敏度核，这种三维空间函数描述了太阳内部的变化如何转化为日震学观测量的变化。在大多数情况下，这些灵敏度核来自于利用最先进太阳模型进行的正向建模。目标：我们旨在通过将灵敏度核的体积分与日震学走时的测量值进行比较，来测试这些灵敏度核。方法：通过操纵跟踪速率，我们模拟了存在于Dopplergram数据立方体中的额外纬向速度。然后，这些数据立方体由标准的走时测量流水线进行处理。我们研究了盘心周围方框内平均的东西向走时对植入跟踪速度的依赖关系。这种依赖关系的斜率与所使用的走时几何形状对应的灵敏度核的总体积分成正比。结果：我们发现，对于应用了ridge filtering的走时，测量值和模型之间具有很好到可接受的一致性。所寻求的依赖关系确实类似于线性函数，且其斜率与正向建模灵敏度核预期的体积分相一致。对于phase-speed filtered数据立方体，这种一致性则不那么乐观。对于最小的phase speeds（滤波器td1--td4），不一致性尤为明显；对于较大的phase speeds，我们的结果表明，测量到的核积分在系统上大于正向建模的预期值。我们承认，对于大phase-speeds和更高的径向模式，我们的测试程序可能并不合适。
英文摘要：
Context: Helioseismic inversions rely largely on sensitivity kernels, 3-D spatial functions describing how do the changes in the solar interior translate into the changes of helioseismic observables. These sensitivity kernels come in most cases from the forward modelling utilising state-of-the-art solar models. Aims: We aim to test the sensitivity kernels by comparing their volume integrals with measured values from helioseismic travel times. Methods: By manipulating the tracking rate, we mimic the additional zonal velocity present in the Dopplergram datacubes. These datacubes are then processed by a standard travel-time measurements pipeline. We investigate the dependence of the east--west travel time averaged over a box around the disc centre on the implanted tracking velocity. The slope of this dependence is directly proportional to the total volume integral of the sensitivity kernel corresponding to the used travel-time geometry. Results: We find a very good to acceptable agreement between measurements and models for travel times with ridge filtering applied. The sought dependence indeed resembles a linear function and the slope of it agrees with the expected volume integral from the forward-modelled sensitivity kernel. The agreement is less optimistic for the phase-speed filtered datacubes. A disagreement is particularly large for smallest phase speeds (filters td1--td4), for the larger phase speeds, our result indicate that the measured kernel integrals are systematically larger than expected from the forward modelling. We admit that for large phase-speeds and higher radial modes our testing procedure does not have to be appropriate.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
