Science is a wonderful thing if one does not have to earn one’s living at it. -----Albert Einstein

1. Science is a wonderful thing if one does not have to earn one’s living at it. -----Albert Einstein

2. Lecture 1: 日震学的意义及观测 Lecture 2-3: time-distance 日震学 Lecture 4: global日震学 Lecture 5: ring-diagram日震学 Lecture 6: 未来的日震学及展望 两节上机实习课

3. 日震学在太阳物理中的意义及日震学的观测 赵俊伟 斯坦福大学汉森试验物理实验室

4. A New Era Is Coming for Solar Physics Research!

6. Shock waves generated by the rocket carrying SDO

7. Waves Are Everywhere!

8. Earthquake: Seismic Waves Courtesy: CalTech Seismology Laboratory

9. Earthquake and Seismology Left: Earthquakes often cause damages. The main entrance to Stanford University collapsed due to 1906 San Francisco Earthquake. Right: Earthquake can also do good to science. Seismology can help researchers to investigate the Earth’s interior. Figures courtesy: Stanford Report, Nature

10. 海啸: Tsunami Waves Generated by Chilean 8.9 Magnitude Earthquake

11. Sunquake: Helioseismic Waves Kosovichev & Zharkova, 1998, Nature

12. EIT Waves

13. Possible MHD Waves in Chromosphere Okamoto et al. 2007, Science

14. Just like seismology which studies seismic waves to derive Earth’s interior structures, helioseismology is a science to study solar interior properties by studying helioseismic waves.

15. Why do we study helioseismology?

16. Sunspots on the Solar Surface courtesy: SOHO/MDI

17. Hinode 观测到的一个黑子群

18. 太阳活动区的浮现与消失

19. Why Do We Study Helioseismology? • Solar surface magnetic field We wonder where these magnetic field come from and where they go. We also wonder why these sunspots remain there for some time, and why they decay away.

20. SOHO/EIT Observation

21. Sunspot Butterfly Diagram

22. Magnetic Field Butterfly Diagram

23. Why Do We Study Helioseismology? • Solar surface magnetic field We wonder where these magnetic field come from and where they go. We also wonder why these sunspots remain there for some time, and why they decay away. • Solar activity cycles Why does the Sun have 11-year activity cycles? Why did the Sun experience a very low and a very long minimum from 2007 to 2009?

24. Violent Solar Eruptions courtesy: EIT, LASCO

25. 太阳风暴中的彗星

26. SOHO搭载的几架仪器观测到的太阳现象

27. Auroras on Planets Caused by Solar Storms Left: persistent Saturnian auroras around its south pole Right: Auroras seen in high latitude areas on the Earth Figures credit: APOD

28. Why Do We Study Helioseismlogy? • Solar surface magnetic field We wonder where these magnetic field come from and where they go. We also wonder why these sunspots remain there for some time, and why they decay away. • Solar activity cycles Why does the Sun have a 11-year activity cycle? Why did the Sun experience a very low and a very long minimum in the past 2 years or so. • Solar storms and bad space weather Solar storms may cause great troubles to man-made satellites in space and even power grids on the Earth. We wonder if we can better forecast space weather by a better understanding of the solar interior.

29. The Sun Rotates 400 years ago, Galileo Galilei observed the Sun’s rotation by tracking sunspots on its surface. Only very recently, scientists began to reveal solar interior rotation speed and meridional flow fields by use of helioseismology. (courtesy: Rice Galileo Project)

30. 太阳的较差自转是太阳磁场形成的原因

31. Why Do We Study Helioseismology? • Solar surface magnetic field We wonder where these magnetic field come from and where they go. We also wonder why these sunspots remain there for some time, and why they decay away. • Solar activity cycles Why does the Sun have a 11-year activity cycle? Why did the Sun experience a very low and a very long minimum in the past 2 years or so. • Space storms and bad space weather Space storms may cause great trouble to man-made satellites in space and even power grids on the Earth. We wonder if we can better forecast space weather by a better understanding of solar interior. • Solar interior rotational and meridional flows Precise determination of solar interior rotational and meridional flow fields are crucial to understand solar dynamo.

32. 日震学的观测

33. 我们能否观测恒星的内部? At first sight it would seem that the deep interior of the Sun and stars is less accessible to scientific investigation than any other regions of the universe. Our telescopes may probe farther and farther into the depths of space; but how can we ever obtain certain knowledge of that which is hidden behind substantial barriers? What appliance can pierce through the outer layers of a star and test the conditions within? (written in 1926) Sir Arthur Eddington (1882 – 1944)

34. 我们可以利用声音观测到肉眼所不能看到的东西.我们可以利用声音观测到肉眼所不能看到的东西. 可以用声音观测吗?

35. Investigate the Solar Interior by Analyzing Sound of the Sun Various information regarding the solar interior structures and dynamics have been obtained from helioseismology analyses

36. 日震学的观测:地面观测 美国国立太阳天文台Global Oscillation Network Group (GONG) 日震学需要长达数小时甚至数天的连续观测。若做到这一点，一个办法就是夏季去南极观测，而早期的日震观测就是这样做的；另外一个办法就是环绕地球多处设置观测站。 Figure courtesy: GONG/NSO

37. 日震学的观测:空间观测 空间观测，既可以实现时间上的连续性，又可以做到seeing-free. 但是问题是，如果出现故障，无法排除，而且造价通常 较高。

38. 日震学的观测:空间观测 日本的Hinode也进行日震学观测。但是由于其多普勒速度场的观测不能如预期实现，只能使用其G-Band 和CaH的观测，使得结果也不如预期。但是可以用于太阳极区的日震学研究，是其它观测所不能做到的。 右图显示了Hinode跟SOHO/MDI的k-图与time-distance图的比较。

39. 日震学的观测:空间观测 AIA SDO(Solar Dynamics Observatory)将如期在今年12月份发射。HMI(Helioseismic Magnetic Imager)将进行日震学与太阳横向和纵向场的观测。斯坦福大学成为HMI和AIA的数据中心，每天接受大约2.0TB的数据。 太阳能板 HMI EVE