演講資訊

摘要：

Solar magnetic fields are responsible for most activities on the Sun. Understanding how and where they are generated is a central issue in solar physics. Most theories predict that magnetic fields are generated by dynamo near the base of the convection zone (BCZ), located at 0.71 solar radius. However, so far no confirmed evidence has been found near the BCZ. Various helioseismological methods used to probe magnetic fields at the BCZ are reviewed, and then our recent method, "solar-cycle variations of meridional flows", is discussed in detail. Using SOHO/MDI data, we measure the latitudinal distribution of meridional flow signals in the solar interior down to 0.54 solar radius, over 15 years, including two solar minima and one maximum. The result shows that the signals near the BCZ at the maximum are different from those at two minima, suggesting the existence of magnetic field near the BCZ.