1. VFISV update and effects of the variation of HMI filter profiles on the inversions R. Centeno and S. Tomczyk Rebecca Centeno SDO SWG meeting -- Sept 9, 2009

2. VFISV update Filter profiles HMI data VFISV description VFISV current status Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 5-6 spectral points 4-6 modulation states Cadence: ~90-120 seconds ~12-minute averages for magnetic field measurements (Borrero et al. 2007) 4096x4096 pixels HMI data

3. VFISV update Filter profiles HMI data VFISV description VFISV current status Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Forward modeling: Milne-Eddington approximation with Zeeman-induced Stokes profiles Filtering: Synthetic profiles are computed at high spectral resolution and then filtered with HMI’s filter profiles Inversion: Levengberg-Marquardt iterative scheme tries to match synthetic Stokes profiles to observed data in a least- squares sense. Free parameters: , B, , , v LOS,  0,  D, , B 0, B 1 VFISV Borrero et al 2009

4. VFISV update Filter profiles HMI data VFISV description VFISV current status Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 12500 inversions per second! But is straightforward parallelizable. F90 inversion code has been thoroughly tested and is working fine. Version 1.05 works with HMI-like data (actually filters Hinode SP Stokes data with HMI filter profiles and then inverts 6 point spectral lines). Code has been implemented into pipeline (R. Bogart) Some issues with the C wrapper VFISV

5. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Filter profiles change across the FOV: amplitudes, integrated areas, shapes, side-lobes, spectral shifts. Filter profiles variation across the FOV

6. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Filter profiles change across the FOV: amplitudes, integrated areas, shapes, side-lobes, spectral shifts.  This can have effects on the inversion results: velocity, magnetic field strength and topology… Filter profiles variation across the FOV

7. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Filter profiles change across the FOV: amplitudes, integrated areas, shapes, side-lobes, spectral shifts.  This can have effects on the inversion results: velocity, magnetic field strength and topology…  We have to invert approx. 4096x4096 pixels every 10 minutes Filter profiles variation across the FOV

8. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Filter profiles change across the FOV: amplitudes, integrated areas, shapes, side-lobes, spectral shifts.  This can have effects on the inversion results: velocity, magnetic field strength and topology…  We have to invert approx. 4096x4096 pixels every 10 minutes  We can’t afford to compute the filter profiles for each pixel!! Filter profiles variation across the FOV

9. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Filter profiles variation across the FOV Is it reasonable to use a unique set of HMI filter profiles for all the pixels in the inversions?

10. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Statistical properties: AMPLITUDES Flatfielding will take care of the area differences among the filters

11. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Statistical properties: SHIFTS We expect the filter shifts to affect the retrieved velocities

12. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Statistical properties: SKEWNESS Differences in shapes could affect other quantities

13. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Inversions Hinode SP data

14. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Inversions Hinode SP data HMI fake Stokes 64x64 HMI filters

15. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Inversions Hinode SP data HMI fake Stokes 64x64 HMI filters central filters correct filters shifted central filters 3 inversions

16. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Inversions Hinode SP data HMI fake Stokes 64x64 HMI filters central filters correct filters shifted central filters 3 inversions Reference results Residual differences Residual differences

17. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Inversions Hinode SP data HMI fake Stokes 64x64 HMI filters central filters correct filters shifted central filters Reference results Residual differences Residual differences Are they good enough? 3 inversions

18. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Results Inversion results for magnetic pixels: central filters V LOS Magnetic field strength

19. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Results Inversion results for magnetic pixels: central filters V LOS Magnetic field strength Magnetic properties don’t notice the differences in shapes, amplitudes and shifts of the filter profiles!!

20. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Results Inversion results for non-magnetic pixels: central filters V LOS Magnetic field strength

21. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Results Inversion results for non-magnetic pixels: shifted central filters V LOS Magnetic field strength

22. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Results Inversion results for non-magnetic pixels: shifted central filters V LOS Magnetic field strength Residual velocity differences NOT due to filter shifts

23. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Results “Actual” vs. “central” filter profiles:

24. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Results Side-lobe imbalance not well accounted for with central filters “Actual” vs. “central” filter profiles:

25. VFISV update Filter profiles HMI filter profiles Characterization Test inversions Rebecca Centeno SDO SWG meeting -- Sept 9, 2009 Results Filter profiles change across the FOV: amplitudes, integrated areas, shapes, side-lobes, spectral shifts. How does if affect the inversion results?  Changes in HMI filter profiles don’t affect retrieved magnetic properties  Bulk filter shifts affect velocities  Residual effects on velocities from side-lobe imbalance Inversions CAN be carried out with one set of filter profiles BUT careful calibration for retrieved velocities is necessary!