Helioseismic data for solar cycles 23 and 24 have shown unequivocally that solar dynamics changes with solar activity. Changes in solar structure have been more difficult to detect. Basu & Mandel had claimed that the then-available data revealed changes in the He ii ionization zone of the Sun. The amount of change, however, indicated the need for larger than expected changes in the magnetic fields. Now that helioseismic data spanning two solar cycles are available, we have redone the analysis using improved fitting techniques. We find that there is indeed a change in the region around the He ii ionization zone that is correlated with activity. Because the data sets now cover two solar cycles, the time variation is easily discernible.

太阳周期 23 和 24 的日震数据明确表明，太阳动力学随太阳活动而变化。太阳结构的变化更难以检测。巴苏和曼德尔声称，当时可用的数据揭示了太阳He ii电离区的变化。然而，变化量表明需要磁场发生比预期更大的变化。现在可以获得跨越两个太阳周期的日震数据，我们使用改进的拟合技术重新进行了分析。我们发现 He ii电离区周围的区域确实存在与活性相关的变化。由于数据集现在涵盖两个太阳周期，因此时间变化很容易辨别。