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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 - PowerPoint PPT Presentation
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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
VFISV updateFilter profiles
HMI dataVFISV descriptionVFISV 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
VFISV updateFilter profiles
HMI dataVFISV descriptionVFISV 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, , , vLOS, 0, D, , B0, B1
VFISV
Borrero et al 2009
VFISV updateFilter profiles
HMI dataVFISV descriptionVFISV 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
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest 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
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest 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
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest 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
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest 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
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest 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?
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Statistical properties: AMPLITUDES
Flatfielding will take care of the area differences among the filters
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Statistical properties: SHIFTS
We expect the filter shifts to affect the retrieved velocities
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Statistical properties: SKEWNESS
Differences in shapes could affect other quantities
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Inversions
Hinode SPdata
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Inversions
Hinode SPdata
HMI fakeStokes
64x64HMI filters
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Inversions
Hinode SPdata
HMI fakeStokes
64x64HMI filters
central filters
correct filters
shifted central filters
3 inversions
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Inversions
Hinode SPdata
HMI fakeStokes
64x64HMI filters
central filters
correct filters
shifted central filters
3 inversions
Referenceresults
Residual differences
Residual differences
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Inversions
Hinode SPdata
HMI fakeStokes
64x64HMI filters
central filters
correct filters
shifted central filters
Referenceresults
Residual differences
Residual differences
Are they good enough?
3 inversions
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Results
Inversion results for magnetic pixels: central filters
VL
OS
Mag
neti
c fi
eld
stre
ngth
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Results
Inversion results for magnetic pixels: central filters
VL
OS
Mag
neti
c fi
eld
stre
ngth
Magnetic properties don’t notice the differences in
shapes, amplitudes and shifts of the filter profiles!!
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Results
Inversion results for non-magnetic pixels: central filters
VL
OS
Mag
neti
c fi
eld
stre
ngth
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Results
Inversion results for non-magnetic pixels: shifted central filters
VL
OS
Mag
neti
c fi
eld
stre
ngth
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Results
Inversion results for non-magnetic pixels: shifted central filters
VL
OS
Mag
neti
c fi
eld
stre
ngth
Residual velocity differencesNOT due to filter shifts
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest inversions
Rebecca Centeno
SDO SWG meeting -- Sept 9, 2009
Results
“Actual” vs. “central” filter profiles:
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest 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:
VFISV updateFilter profiles
HMI filter profilesCharacterizationTest 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 profilesBUT careful calibration for retrieved velocities is necessary!