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VFISV update and effects of the variation of HMI filter profiles on the inversions

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. HMI data VFISV description VFISV current status. VFISV update Filter profiles. HMI data. 5-6 spectral points

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VFISV update and effects of the variation of HMI filter profiles on the inversions

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  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. HMI data VFISV description VFISV current status VFISV update Filter profiles HMI data • 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 Rebecca Centeno SDO SWG meeting -- Sept 9, 2009

  3. HMI data VFISV description VFISV current status VFISV update Filter profiles VFISV 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, , , vLOS, 0, D, , B0, B1 Borrero et al 2009 Rebecca Centeno SDO SWG meeting -- Sept 9, 2009

  4. HMI data VFISV description VFISV current status VFISV update Filter profiles VFISV 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 Rebecca Centeno SDO SWG meeting -- Sept 9, 2009

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

  6. HMI filter profiles Characterization Test inversions VFISV update Filter profiles Filter profiles variation across the FOV 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… Rebecca Centeno SDO SWG meeting -- Sept 9, 2009

  7. HMI filter profiles Characterization Test inversions VFISV update Filter profiles Filter profiles variation across the FOV 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 Rebecca Centeno SDO SWG meeting -- Sept 9, 2009

  8. HMI filter profiles Characterization Test inversions VFISV update Filter profiles Filter profiles variation across the FOV 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!! Rebecca Centeno SDO SWG meeting -- Sept 9, 2009

  9. HMI filter profiles Characterization Test inversions VFISV update Filter profiles 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? Rebecca Centeno SDO SWG meeting -- Sept 9, 2009

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  25. HMI filter profiles Characterization Test inversions VFISV update Filter profiles 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! Rebecca Centeno SDO SWG meeting -- Sept 9, 2009

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