1. Helioseismic Magnetic Imager and Why We Study Helioseismology Junwei Zhao W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA94305-4085

2. Lecture Plans Lecture 1 HMI and why we want to do helioseismology studies Lecture 2 HMI routine helioseismology results that you can download and Use Lecture 3 Some helioseismology studies that may interest you

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

5. Shock waves generated by the rocket carrying SDO

6. Waves Are Everywhere!

7. Earthquake: Seismic Waves Courtesy: CalTech Seismology Laboratory

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

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

10. EIT Waves

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

12. Half of HMI is Helioseismic, and the other half is Magnetic. 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.

17. Why do we study helioseismology?

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

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. 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

26. 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.

27. 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)

28. 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.

29. Undoubtedly, helioseismology is very important to understand our star, the Sun. That is why NASA spends hundreds of millions of dollars to sponsor HMI.

32. Shift with time due to Michelson drift. (black is April and red is July) Daily variation in equatorial rotation speed.

34. Instrument Status - Milestones Launch: February 10, 15:23UT Power : February 14, 01:44 Open door: March 24, 15:04UT – First light Science data: March 24, 23:10UT – About 94% coverage since then. Regular operations: April 30, 22:24UT – More than 99.9% complete – Regular observables>99% of time HMI first light

35. Eclipse Interrupts Data

36. One Image of the Sun

37. Granulation on Solar Surface

38. Full-Disk Dopplergram

39. Full Coverage of Emerging Active Region

40. Performance – Power Spectrum Courtesy Tom Duvall