1. LINE OF SIGHT MAGNETIC FIELD EVOLUTION & 120310 DATA ANALYSIS Dandan Ye

2. Content  Part 1 Line of Sight magnetic field evolution  Part 2 120310 SDO data analysis

3. Line of Sight magnetic field evolution  Paperview:  Flare Energy and Magnetic Field Variations H. S. Hudson, G. H. Fisher, B. T. Welsch

4.  Introduction:  Magnetic field created in convection zone and then ascends through the photosphere and emerges into the corona. The emerged flux contains embedded stresses that may accumulate for some period of time and then relax, producing a flare and/or a CME.  The photospheric vector magnetic field might vary across the duration of a solar flare or CME.

5. Line of Sight magnetic field evolution Perhaps the first clear illustration of a flare-associated magnetic field change (Wang 1992)

6. Line of Sight magnetic field evolution  Simple model: to estimate the energy deposited in the subphotospheric layers in this back-reaction  Principle: any change of magnetic field energy must lead to a corresponding change in magnetic pressure

7. Line of Sight magnetic field evolution  Conclusion:  They predict that flares can be accompanied by rapid and irreversible changes of photospheric magnetic fields.

8. Line of Sight magnetic field evolution  OBSERVATIONAL EVIDENCE OF BACK REACTION ON THE SOLAR SURFACE ASSOCIATED WITH CORONAL MAGNETIC RESTRUCTURING IN SOLAR ERUPTIONS Haimin Wang and Chang Liu provides support for the theory and prediction of Hudson : photospheric magnetic fields must respond to coronal field restructuring and turn to a more horizontal state near the PIL after eruptions.

9. 20120310 SDO data

10.  HMI magnetogram  AIA 171 304 1600

11. 20120310 SDO data

15. Next Steps  Analyzing the line-of-sight magnetic field evolution of the 20121023 X-class flare as a practice  Try to do a running average of flow-field data on 20120701  Doing some study about the flares on 20120310

16. Thanks!