study o horizontal flows in solar active regions
DESCRIPTION
This thesis work can be framed in a more general concept designated as "high-solution in solar physics". The work consists of two clearly defined parts. The first part concerning instrumental developments for solar observations and the second one devoted to the scientific exploitation of solar data acquired with cutting edge solar instrumentation.TRANSCRIPT
THESIS DISSERTATIONTHESIS DISSERTATION
Study of horizontal flows in solar active regions
high-resolution image reconstruction techniquesbased on
Santiago Vargas Domínguez
Supervisors: Valentín Martínez Pillet & Jose A. Bonet
La Laguna, Tenerife - Dic 2008
La Laguna, Tenerife - Dic 2008
THESIS DISSERTATIONTHESIS DISSERTATION
Study of horizontal flows in solar active regions
high-resolution image reconstruction techniques
Santiago Vargas Domínguez
Supervisors: Valentín Martínez Pillet & Jose A. Bonet
based on
Santiago Vargas Domínguez
La Laguna, Tenerife - Dec 18, 2008
Study of horizontal flows in solar active regions
high-resolution image reconstruction techniques
based on
THESIS THESIS DISSERTATIONDISSERTATION
Supervisors: Jose Antonio Bonet & Valentín Martínez Pillet
PART 1 Defining a method for in-flight calibration of IMaX aberrations
PART 2 Study of proper motions in solar active regions
Outline
PART 1Defining a method for in-flight calibration of IMaX aberrations
Aim at:Perform numerical simulations to identify and evaluate possible optical error sources in the IMaX instrument.Develop an in-flight calibration method to characterize the aberrations affecting the images in IMaX.Describe and test the robustness of the calibration method.
Outline
PART 1 Defining a method for in-flight calibration of IMaX aberrations
IntroductionImage restoration techniquesIn-flight calibration of IMaX aberrationsConclusions
PART 1 Defining a method for in-flight calibration of IMaX aberrations d) Conclusions
c) In-flight calibration of IMaX aberrations
a) Introductionb) Image restoration techniques
Trying to explain the Trying to explain the physics of the Sun requires physics of the Sun requires
to resolve very tiny to resolve very tiny structuresstructures
PART 1 Defining a method for in-flight calibration of IMaX aberrations d) Conclusions
c) In-flight calibration of IMaX aberrations
a) Introductionb) Image restoration techniques
Earth’s atmosphere can be considered
as an isotropic turbulent medium
Atmospheric turbulence is a major problem we encounter in ground-based observations affecting the image
quality
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introductiona) Introduction
Image degradation is generally described as the combination of 3 main contributions
Structures smearing (blurring)
Global displacements of the image (image motion)
Distortion of structures caused by differential image motion in different patches (stretching)
seeing
First problem to deal with if interested on high resolution
data
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introduction
Solutions:
Space observatories
SOHO
HINODE
Elevated cost of launching,
maintenance and updating
Adaptive Optics
Only pursues low-order corrections
Limited to an isoplanatic patch of a few arcsec
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introduction
Solutions :
Space observatories
Adaptive OpticsPost-facto techniquesPowerful numerical codes for image restoration developed in the last decade.They require a specific observing strategy
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introduction
Image Image formationformation
X
Y
Object plane Image
plane
Object plane Image
plane
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introduction
Text
+
Point in the object plane
observed as a spot
on the image plane
Object plane Image
plane
X
Y
Airy spotImage Image
formationformation
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introduction
TextText
Point Spread Function
Space variantVariability of the transmission system
For a extended object (e.g Sun)
Intensity at each point has a contribution from
the neighborhood
Image Image formationformation
PSF =
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introduction
TextText
Image restorationImage restoration
Image restoration fits into the Inverse Problem in Physics that can be considered as the solution of the Fredholm Inhomogeneous equation of the 1st kind.
The kernel is the PSF
Using the convolution theorem,
True objectwhere q is the vectorial notation for the coordinates in the image points
Isoplanatic assumption
Optical Transfer Function (OTF)
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introduction
TextText
Noise Noise contribution and contribution and
filteringfiltering
Restoration filter (Wiener-Helstrom)
Additive noise
Some models for SNR are commonly assumed (Collados, 1986)
Phase Diversity Phase Diversity techniquetechnique
PART 1 Defining a method for in-flight calibration of IMaX aberrations
b) Image restoration techniquesa) Introduction
d) Conclusions
c) In-flight calibration of IMaX aberrations
focus-defocus image pairsPSFsnoise additive termstrue object
Noise terms force a statistical solution of the problem
The PD technique was first proposed as a new method to infer phase aberrations working with images of extended incoherent objects formed through an optical system (Gonsalves & Childlaw, 1979).
PART 1 Defining a method for in-flight calibration of IMaX aberrations
b) Image restoration techniquesa) Introduction
d) Conclusions
c) In-flight calibration of IMaX aberrations
Phase Diversity Phase Diversity techniquetechnique
Error metric to be minimized (Paxman et all, 1992)
OTF is the auto-correlation of the generalized pupil
function
Joint phase aberration
Zernikes
Parametrized by the expansion in Zernike polynomials.Non-linear optimization techniques (SVD) are used to minimize the error metric and get the vector, S1, S2 and Io
PART 1 Defining a method for in-flight calibration of IMaX aberrations
b) Image restoration techniques
Restoration techniquesRestoration techniques
MFBDMulti-Frame
Lofdahl, 2002, 1996
Blind Deconvolution
MOMFBDMulti-Object Multi-Frame
Van Noort, Rouppe van der Voort & Löfdahl, 2005
PDPhase Diversity
Results coming up in a few minutes !!!!
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introduction
d) Conclusions
c) In-flight calibration of IMaX aberr.b) Image restoration techniques
Imaging Magnetograph eXperiment
Instituto de Astrofísica de Canarias
Instituto de Astrofísica de Andalucía
Instituto Nacional de Técnica Aeroespacial
Grupo de Astronomía y Ciencias del Espacio
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introduction
d) Conclusions
c) In-flight calibration of IMaX aberr.b) Image restoration techniques
SUNRISEBallon-borne 1-m solar
telescope Aims at: High-resolution Spectro-polarimetric observations of the solar atmosphereTo be flown:
In the framework of NASA Long Duration Ballon Program in 2009 in circumpolar trajectories at 35-40 km.Consist of:Telescope , Image Stabilisation and Light Distribution System
, IMaX Sunrise Filter Imager (SUFI)
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
spsp
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
ISLiD - Image Stabilisation and Light Distribution System
For simultaneous observations with all science instruments based on di-electric dichroic beam splitters.Includes the Correlator and Wavefront Sensor
IMaX - Imaging Magnetograph eXperimentMagnetograph providing fast cadence two-dimensional maps of complete magnetic field vector and the LOS velocity as well as white-light images with high-spatial resolution.
SUFI - Sunrise Filter ImagerFiltegraph for high-resolution images in the visible and the UV spectral lines.
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
IMaX description
Aim at:Provide magnetograms of extended solar regions by combining high temporal cadence and polarimetric precision, working as:
High-efficient image acquisition system
Near diffraction limited imager
High resolving power spectrograph
High sensitivity polarimeter
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Cameras
Etalon
Electronics box
A glass-plate can be optionally intercalated in one of the IMaX imaging channels to get simultaneous focus-defocus image-pairs, i.e. Phase Diversity (PD) image-pairs, from which an estimate of the aberrations will be possible in post-processing by means of a PD inversion code.Assuming a long-term variation in the aberrations, their calibration could be performed with a cadence of one hour. A burst of 25-30 PD-pairs in the continuum would be enough each time.
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Calibration of aberrations in IMaX
We have included in IMaX a system to calibrate the image degradation during the flight that should allow a correction of the residual aberrations in the science images.
diversity
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introduction
d) Conclusions
c) In-flight calibration of IMaX aberr.b) Image restoration techniques
Strategy
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Testing the robustness of the calibration method
Evaluate the robustness of the method versus a variety of aberration assumptions
Isoplanatic patch
True object
Synthetic image (Vöegler et al. 2005)
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Testing the robustness of the calibration method
Simulate the formation of PD image-pairs produced by 1-m telescope and a given set of aberrations. 30 for diff. photon
noise realizationsImage-pairs are inverted with the PD code.
Set of averaged aberrations retrieved from inversions are compared to input aberrations.
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Identifying error sourcesThe contribution from the error sources can be mathematically represented through the generalized pupil function,
Phase diverse
Transmission function over pupil
Main polishing
error Phase error from etalon
Low-order aberrations
Atm. aberration (IMaX=0)
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Quantifying error sources contributionFirst step is the compilation of data from the design and specifications of all different components
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Low-order aberrations (LOA)
Empirical measurements for the assembled instrument.
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Amplitude in double-pass
Phase in double-pass| H(,) | e (,)
Etalon Screens
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Main mirror polishing errors
Ripple screenHigh-order aberrations
Average power spectrum matches a von Karman power
spectrum
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Phase Diversity plate
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Detector contribution
A detector element performs a spatial integration of the irradiance falling onto its surface
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Simulations
We classify error contributions in 3 groups:
Low-order aberrations (LOA)
High-order aberrations (HOA)
Detector contribution & Noise
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Simulations
ERROR SOURCE
CONTRIBUTIONEXPERIMENT
1 2 3 4
rms-ripple 0, 2/60, 2/28 waves
rms-LOA0, 1/12, 1/7, 1/4, 1/3, 1/2
waves
rms-noise 10-3 x continuum signal
rms-etalon 1/26 waves
Etalon amplitude | H(,) | ≠ 1
CCD 12 m/pix
PD-defocus
DEGRADATION/INVERSION8.51 mm (PV 1.00) / 8.51
mm9.00 mm (PV 1.06) / 8.51
mm
A pessimistic case for IMaX + ISLiD + Telescope performance
PART 1 Defining a method for in-flight calibration of IMaX aberrations
c) In-flight calibration of IMaX aberr.
Error contribution
srms-ripple=2/60rms-etalon=/26rms-noise=10-3
CCD
rms-LOA=/5
Focus image of a PD-pair True object(from 30 realizations)
RESULTSRESULTS
Degraded Restored True
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introductionb) Image restoration techniques
d) Conclusionsc) In-flight calibration of IMaX aberrations
A method for the in-flight calibration of aberrations in IMaX has been proposed.The robustness of the method has been tested by numerical experiments simulating different aberration components.Sources of aberration have been modeled and added in every subsequent experiment.The repercussion of every new added ingredient in the final result from the inversions has been evaluated.
In the PART 1 of this work:
The calibration method has proved to give satisfactory results even in under pessimistic aberration conditions
PART 1 Defining a method for in-flight calibration of IMaX aberrations
a) Introductionb) Image restoration techniques
d) Conclusionsc) In-flight calibration of IMaX aberrations
Main conclusions are:The PD-code does not accurately reproduce the shape of the WFE but provides reliable OTFs for satisfactory restorations.Inhomogeneities in the etalon transmission are converted into some extra errors in the resulting wavefront that partially compensate the loss of contrast caused by unsensed HOA.Experiment 3 validates the method proposed to calibrate the errors in the images of IMaXThe amount of defocus (diversity) produced by the PD plate is a critical parameter for an optimal performance of the PD code. An error of 0.5 mm in the determination of the diversity value can caused an over restoration of about 5%.
PART 2Study of proper motions in solar active regions
Aim at:
Analysis of horizontal proper motions, at a photospheric level, around solar active
regions from ground-based and space high-resolution time series.
Nearly 1000000 images have been Nearly 1000000 images have been used for this study !!!used for this study !!!
Outline
Solar active regionsProper motions in a complex ARMoat flows surrounding sunspotsFlow field around solar poresConclusions
PART 2 Study of proper motions in solar active regions
a) Solar active regionsb) Proper motions in a complex AR
d) Flow field around solar porese) Conclusions
c) Moat flows surrounding sunspots
PART 2 Study of proper motions
in solar active regions
Are the evident manifestation of the solar activity
Sunspots
Are interpreted as complex structures having strong magnetic fields that inhibit the plasma convection (temperature lower
than the surrounding photosphere)
a) Solar active regionsb) Proper motions in a complex AR
d) Flow field around solar porese) Conclusions
c) Moat flows surrounding sunspots
PART 2 Study of proper motions
in solar active regions
Structure of Sunspots The responsible for the origin and structure is
believed to be the toroidal magnetic flux in the solar interior (Schüssler et al, 2002)
Cluster (spaguetti) : Mag. field divides into many separate flux Parker, 1979 tubes in the first Mm below the surface
Models
Monolithic : Mag. field underneath the solar surface is Cowling, 1957 confined to a single flux tube.
a) Solar active regionsPART 2 Study of proper
motions in solar active
regions
UmbraCoolest part of the
sunspots~ 3500 - 5000 K
Strong Mag.F inhibits convectionVertical magnetic field; more inclined at umbra-penumbra boundary
~ 2000 - 3500 Gauss in average
Energy radiation 20% photosphere
Features (umbral dots, light bridges)
PenumbraFilamentary bright/dark
structure
The first one has been extensively tested 2 different orientations of mag. field coexist
Energy radiation 75% photospheric
Mag. Field inner part: ~1500 Gauss outer part: ~700 Gauss
Vertical component (~60-70 deg)Horizontal component
Different models try to explain the structure of the penumbra: Uncombed, Gappy, MISMAS.
a) Solar active regionsPART 2 Study of proper
motions in solar active
regions
Evershed Flow
Associated to an observational effect in the penumbra registered as a global wavelength shift for spectral lines forming in the penumbrae of sunspots.
a) Solar active regionsPART 2 Study of proper
motions in solar active
regions
Photosphere surrounding sunspots
Convective flows & large-scale plasma circulation plays and important role in dynamics and evolution of solar active regions (Schrijver & Zwaan 2000).
Granular convective pattern surrounding sunspots is perturbed by the presence of magnetic elements, moving magnetic features (MMF).
MMF’s move radially outward through an annular cell called “moat”. (Sheeley 1972, Harvey & Harvey 1973).
a) Solar active regionsPART 2 Study of proper
motions in solar active
regions
Moat flow
(Meyer et al. 1974)
Could be:
Typical cell scale of up to 104 km.
A supergranule.
Center occupied by a sunspot.
(Nye et al. 1988)
Excess temperature and pressure generated have been proposed as origin of moat.
Sunspot would act as a blocking agent to the upward propagation of heat from below.
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Averaged horizontal velocities [m s-1]
a) Solar active regionsPART 2 Study of proper
motions in solar active
regions
+ Young spots
♢ Old Spots
Sobotka & Roudier, 2007
d) Flow field around solar porese) Conclusions
c) Moat flows surrounding sunspots
PART 2 Study of proper motions
in solar active regions
a) Solar active regionsb) Proper motions in a complex solar AR
Observations1m - Solar Swedish Tower
(SST) Roque de los Muchachos Observatory, La
Palma.
NOAA AR10786 9-Jul-2005
G-band, G-cont 7:47 – 9:06 UT
DC
G-band δ-configuration sunspot
PART 2 Study of proper motions
in solar active regions d) Flow field around solar pores
e) Conclusions
c) Moat flows surrounding sunspots
a) Solar active regionsb) Proper motions in a complex solar AR
Processing
Flat-fielding & dark-current substraction
Image restoration MOMFBD + PD
De-rotation and alignment
De-stretching and p-modes
filtering
Time series
G-band and G-cont
428 images each
Cadence: 10.0517 s
71 minutes
FOV 57.8” x 34.4”
Image restoration MOMFBD + PD
Low quality
Medium quality
Good quality
Restored quality
Nº Images : 428 Duration : 71 minutes Cadence : 10.0517 s Pixel size : 0.041 “/pix
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MoatNo Moat
Exploding granules draggedby the moat flow (elongated)
Recurrent exploding granules
PART 2 Study of proper motions
in solar active regions
b) Proper motions in a complex solar AR
Map of displacements
We have used the G-band series to study proper motions of the structures by local correlation technique (LCT)
Finding local concordances between two frames (correlation window).First applied by November & Simon (1988) to measure proper motions in solar granulation.Used at diff. spatial scales to study solar dynamics (e.g supergranulation Shine,Simon & Hurlburt, 2000)
Gaussian tracking window FWHM = 0.78” (half of typical granular size)
Map of horizontal displacements averaged over the whole series
[Mm]
PART 2 Study of proper motions
in solar active regions
b) Proper motions in a complex solar AR
General description of proper motions
Neutral LinesFlowmap
Exploding granules
SOUP magnetogramsMOMFBD+PD
Combining 1500 images
SNR=200Resolution: 0.2 “/pix
PART 2 Study of proper motions
in solar active regions
b) Proper motions in a complex solar AR
Moats
Vmoats = 0.67 km/sVh > 0.4 km/s
Moats are closely associated with the presence of a penumbra.
Low velocity threshold: 400 m/s
PART 2 Study of proper motions
in solar active regions
b) Proper motions in a complex solar AR
None of the pores is associated with any moatlike flow.
Strong neutral line Not clear evidence of moat flow Moats are absent in granulation regions located next to penumbral sides paralell to the direction of the filaments.
PART 2 Study of proper motions
in solar active regions
b) Proper motions in a complex solar AR
Conclusions
We have detected strong outflows (moats) associated to penumbrae (mean speed 0.67 km/s, rms=0.32 km/s)
Furthermore, moats do not developed in directions transversal to the penumbral filaments.
Evidence suggestive of a link between moat flow and flows aligned with penumbral
filaments (EF)
Umbral core sides with no penumbrae do not display moat flows.
Neutral lines are seem to play a role in the inhibition of moat flows in places where they are expected to be generated.
PART 2 Study of proper motions
in solar active regions
b) Proper motions in a complex solar AR
Recent findings by Sainz Dalda & Martínez Pillet (2005), and Ravindra (2006) establish that the penumbral filaments extend beyond the photometric sunspot boundary and cross the region dominated by the moat flow. Cabrera Solana et al (2006) found Evershed clouds as precursors of MMFs around sunspots.
d) Flow field around solar porese) Conclusions
PART 2 Study of proper motions
in solar active regions
b) Proper motions in a complex AR
c) Moat flows surrounding sunspots
a) Solar active regions
Extend the sample of solar active regions to consolidate the previous conclusions.
Aim at:
i.e establish whether the moat-penumbrae relation is sistematically found in other active regions.
By using:
Gound-based high-resolution observations
7 different sunspots series.
Sunspots with different penumbral configurations.
d) Flow field around solar porese) Conclusions
PART 2 Study of proper motions
in solar active regions
b) Proper motions in a complex ARc) Moat flows surrounding sunspots
a) Solar active regions
1m - Solar Swedish Tower (SST) S1 AR440, 22 Aug 2003
S2 AR608, 10 May 2004
S5 AR789, 13 Jul 2005
S6 AR813, 04 Oct 2005
S3 AR662, 20 Aug 2004
S7 AR893, 10 Jun 20061
2
345
6
7
Observations
S4 AR662, 21 Aug 2004
Restoration MFBD/MOMFB
Time series > 40 min
PART 2 Study of proper motions
in solar active regions
c) Moat flows surrounding sunspots
Masking moats in 8 steps
1. Select the FOV to analyze.2. Create a binary mask for the sunspots.
3. Compute the proper motions by LCT.
4. De-project velocities.
5. Create a binary mask using a velocity threshold.
6. Apply the mask to the flowmap in 3.
7. Create a binary mask of moats.
8. Plot the final flow map showing the moat flows.
PART 2 Study of proper motions
in solar active regions
c) Moat flows surrounding sunspots
Moat flows around sunspots (flowmaps)
Penumbral filaments extending radially from the umbra
Peculiar regions
PART 2 Study of proper motions
in solar active regions
c) Moat flows surrounding sunspots
Penumbral filaments curved, tangential to
sunspot border No moatlike flows
PART 2 Study of proper motions
in solar active regions
c) Moat flows surrounding sunspots
Neutral lines affecting the flow behaviour
PART 2 Study of proper motions
in solar active regions
c) Moat flows surrounding sunspots
Conclusions
Moat flows are oriented following the direction of the penumbral filaments.
Umbral core sides with no penumbra do not display moat flows.
Moat do not develop in the direction transverse to the penumbral filaments.
No evidence of moats following penumbral filaments when having a change in the magnetic polarity.
b) Proper motions in a complex AR
e) Conclusions
c) Moat flows surrounding sunspots
PART 2 Study of proper motions
in solar active regions
a) Solar active regions
d) Flow field around solar pores
Observing and analyzing pores. Since they do not have penumbra at all, our main conclusions. about moat-penumbra relation can be tested.
Aim at:
By using:
Gound-based and space observations.
Pores time series.
b) Proper motions in a complex AR
e) Conclusions
c) Moat flows surrounding sunspots
a) Solar active regions
d) Flow field around solar pores
Ground-based observationsSST
30 Sep 2007
Study of proper motions in solar active regions
Active region NOAA 10971
Standard reduction and processing
MOMFBD reconstructions
G-band time series (50 min)
MOMFBD restorations
d) Flow field around solar poresStudy of proper motions in solar active regions
d) Flow field around solar pores
General description of proper motions
Study of proper motions in solar active regions
Exploding granules
d) Flow field around solar pores
Space observationsHINODE
1 June 2007
30 Sep 2007
Study of proper motions in solar active regions
Coordinated obs. with SST
Alignment and subsonic filtering
60 min
14 hours
HINODE during14 hours
d) Flow field around solar pores
Long-term evolution of the velocity field
Study of proper motions in solar active regions
d) Flow field around solar pores
Distribution of horizontal speeds
Velocity magnitudes
Low< 0.3 km/s
Study of proper motions in solar active regions
d) Flow field around solar pores
Velocity distribution around solar pores
Study of proper motions in solar active regions
d) Flow field around solar poresStudy of proper motions in solar active regions
Pore center
Radial directions
Inward (-)
Outward (+)
t
r
r
d) Flow field around solar poresStudy of proper motions in solar active regions
Flow mapGradients
Radial directionsCos
Mask
d) Flow field around solar poresStudy of proper motions in solar active regions
Results
InOut
FOVFOV
Cos Cos
d) Flow field around solar poresStudy of proper motions in solar active regions
Outflows display larger velocity magnitudesInflows display lower velocity magnitudes
Conclusions
First time we tested our algorithms in HINODE data. Flows calculated from different solar observations are coherent and show the overall influence of exploding events in the granulation around pores.
Motions toward the pores in their nearest vicinityare dominant and are observed systematically.
These motions are basically influenced by external plasma flows deposited by the exploding events.
Definitely, there are no signs of moatlike flows around the pores.
b) Proper motions in a complex AR
d) Flow field around solar poresc) Moat flows surrounding sunspots
PART 2 Study of proper motions
in solar active regions
a) Solar active regions
e) Conclusions
Overall Conclusions
The required software for restoration/inversion of IMaX images has been implemented in the context of this thesis and we make it available for the team.
Our simulations validate the method proposed to calibrate the errors in the images of IMaX.
PART 1 Defining a method for in-flight calibration of IMaX aberrations
We have developed a method for the in-flight calibration of aberrations in IMaX.
Note: Only 4 slides left !!
Moats do not appear in directions transversal to the penumbral filament ones.
All detected properties for moats are also applicable to the Evershed Flow.
Moats develop following the direction of the penumbral filaments in granulation surrounding sunspots.
There are no signs of moatlike flows around the pores.
Overall ConclusionsPART 2 Study of proper motions in solar active regions
Moats are found to be directly correlated to the presence of penumbra in sunspots.
Neutral lines seem to play a role in the inhibition of moats.
Before this work ....
So what ???
Final fate of the EF unknown.
Origin of moat flow unclear.
After this work ....
EF transforms into moat flow.
In agreement with Local Helioseismology (f-modes) evidence: moat flow is only 2
Mm deep.
Acknowledgments
Seidel aberrations
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are needed to see this picture.
PART 2 Study of proper motions
in solar active regions
b) Proper motions in a complex solar AR
Using the map of average velocities we study the evolution of passive corks homogeneously distributed in the FOV
Study of convective cells
d) Flow field around solar pores
Space observationsHINODE
1 June 2007
30 Sep 2007
Study of proper motions in solar active regions
Coordinated obs. with SST
Alignment and subsonic filtering
60 min
14 hours
Moat Granulation
Vh km/s
Threshold used when
plotting velocities !!!
PART 2 Study of proper motions
in solar active regions
c) Moat flows surrounding sunspots
PART 2 Study of proper motions
in solar active regions
c) Moat flows surrounding sunspots
De-projection of horizontal velocities
Measured proper motions are in fact projections of the real horizontal velocities in the sunspot plane onto the plane perpendicular to LOS
Sunspot SystemObserving System
€
v' 2 = v 2 sin2 φ + cos2 φ cos2θ ⎛
⎝ ⎜
⎞
⎠ ⎟
€
tanφ'=tanφ
cosθ
PART 2 Study of proper motions
in solar active regions
b) Proper motions in a complex solar AR
Proper motions inside penumbrae
Link between the moat flow and flows along the penumbral filaments (Evershed flow).
Recent findings by Sainz Dalda & Martínez Pillet (2005), Cabrera Solana et al (2006) and also Ravindra (2006) establish that the penumbral filaments extend beyond the photometric sunspot boundary and cross the region dominated by
the moat flow.
b) Proper motions in a complex AR
d) Flow field around solar poresc) Moat flows surrounding sunspots
PART 2 Study of proper motions
in solar active regions
a) Solar active regions
e) Conclusions
d) Flow field around solar poresStudy of proper motions in solar active regions
Pore center
Radial directions
Inward (-)
Outward (+)
t
r
r
What for ????
The material presented here comes from the analysis of images in the continuum with short exposure times ~10 ms (static atmosphere) and combining many images (~100 continuum, ~1500 SOUP) but still low SNR values are reached.
IMaX will do polarimetry with:
negligible atmospheric turbulence, high SNR, diffraction limit, during hours and furthermore double spatial resolution (from 0.2 to 0.1 arcsec)
Why using speckle ????
The speckle summation has been employed as a way (resource) to determine the robustness of the calibration method we propose to characterize the aberrations in IMaX.
though
in the real case IMaX images are be meant to restored as single PD-pairs with no speckle summation at all.
Image blurring permitted for an instrument can be specified by the diameter of the blur spot or angle subtended by it.
For instance, we can select the angle as the value of the diffraction cut-off that is slightly greater than the Airy FWHM.
Nevertheless this criterion is quite severe and some more flexible ones establish the limit of the defocus tolerance based on the loss of intensity in the central part of the PSF.
Defocus Tolerance
Why PD if it does not reproduce exactly the
WFE ??
We get reliable OTFs to solve our deconvolution problem.
Because
The error metric depends directly on this OTF.
Dispersion of coefficients is low and we do not expectcancellations in the WFE. Repeatability
We have inverted real images for different noise realizations and the dispersion of the wavefront is small.
Why uncorrelated signal and noise assumption ??
Photon noise is certainly a function of the intensity
there are some other noise contributions: Readout and noise related to the fluctuations in
atmospheric transparency which are not
Nevertheless,
Uncorrelated noise and signal is in general a useful approximation giving good results in
simulations
Small-scale irregularities in the wavefront error are notdetectable by the PD-code if we use a finite (rather low) number of Zernike terms.
Please goto Pag 78.
This limitation mainly produces stray-light over the restored image and consequently a loss of contrast.This effect is tolerable within certain margins, and fixes constraints to the polishing quality in the SUNRISE main mirror and the inhomogeneities in the IMaX etalon.
The residual errors in the proposed calibration method induce, in turn,
errors in the subsequent restoration
mean (it - ir) < 2.5% loss of contrast < 5%
IMaX case
QuickTime™ and a decompressor
are needed to see this picture.
5 km