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Study o horizontal flows in solar active regions
 

Study o horizontal flows in solar active regions

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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 ...

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.

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  • Same trend in blue and red histograms. Red one shifted to the right respect to blue. Within the moats, standard velocity values for quiet granulation are still present but with a lower weight.

Study o horizontal flows in solar active regions Study o horizontal flows in solar active regions Presentation Transcript

  • 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 DISSERTATION Supervisors: Jose Antonio Bonet & Valentín Martínez Pillet THESIS DISSERTATION Study of horizontal flows in solar active regions high-resolution image reconstruction techniques based on Santiago Vargas Domínguez Supervisors: Valentín Martínez Pillet & Jose A. Bonet La Laguna, Tenerife - Dic 2008 La Laguna, Tenerife - Dic 2008 THESIS 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
  • PART 1 Defining a method for in-flight calibration of IMaX aberrations PART 2 Study of proper motions in solar active regions Outline
  • PART 1 Defining 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 Introduction Image restoration techniques In-flight calibration of IMaX aberrations Conclusions
  • PART 1 Defining a method for in-flight calibration of IMaX aberrations d) Conclusions c) In-flight calibration of IMaX aberrations a) Introduction b) Image restoration techniques Trying to explain the physics of the Sun requires to resolve very tiny structures
  • PART 1 Defining a method for in-flight calibration of IMaX aberrations d) Conclusions c) In-flight calibration of IMaX aberrations a) Introduction b) 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) 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) First problem to deal with if interested on high resolution data seeing
  • 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 Optics Post-facto techniques Powerful 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 formation Object plane Image plane Object plane Image plane X Y  
  • PART 1 Defining a method for in-flight calibration of IMaX aberrations a) Introduction Text Object plane Image plane Airy spot Image formation + Point in the object plane observed as a spot on the image plane   X Y
  • PART 1 Defining a method for in-flight calibration of IMaX aberrations a) Introduction Text Text Point Spread Function Space variant Variability of the transmission system For a extended object (e.g Sun) Intensity at each point has a contribution from the neighborhood Image formation PSF =
  • PART 1 Defining a method for in-flight calibration of IMaX aberrations a) Introduction Text Text Image restoration Image restoration fits into the Inverse Problem in Physics that can be considered as the solution of the Fredholm Inhomogeneous equation of the 1 st kind . The kernel is the PSF Using the convolution theorem, True object where 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 Text Text Noise contribution and filtering Restoration filter (Wiener-Helstrom) Additive noise Some models for SNR are commonly assumed (Collados, 1986)
  • Phase Diversity technique PART 1 Defining a method for in-flight calibration of IMaX aberrations b) Image restoration techniques a) Introduction d) Conclusions c) In-flight calibration of IMaX aberrations focus-defocus image pairs PSFs noise additive terms true object 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). Noise terms force a statistical solution of the problem
  • PART 1 Defining a method for in-flight calibration of IMaX aberrations b) Image restoration techniques a) Introduction d) Conclusions c) In-flight calibration of IMaX aberrations Phase Diversity technique 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, S 1 , S 2 and I o
  • PART 1 Defining a method for in-flight calibration of IMaX aberrations b) Image restoration techniques Restoration techniques MFBD Multi-Frame Lofdahl, 2002, 1996 Blind Deconvolution MOMFBD Multi-Object Multi-Frame Van Noort, Rouppe van der Voort & Löfdahl, 2005 PD Phase 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 SUNRISE Ballon-borne 1-m solar telescope Aims at: High-resolution Spectro-polarimetric observations of the solar atmosphere To 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.
  • sp 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 eXperiment Magnetograph 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 Imager Filtegraph 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. Image-pairs are inverted with the PD code. Set of averaged aberrations retrieved from inversions are compared to input aberrations. 30 for diff. photon noise realizations
  • PART 1 Defining a method for in-flight calibration of IMaX aberrations c) In-flight calibration of IMaX aberr. Identifying error sources The 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 contribution First 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 screen High-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 CONTRIBUTION EXPERIMENT 1 2 3 4 rms-ripple 0, 2/60, 2/28 waves rms-LOA 0, 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/INVERSION 8.51 mm (PV 1.00  ) / 8.51 mm 9.00 mm (PV 1.06  ) / 8.51 mm
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  • 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 contributions rms-ripple=2  /60 rms-etalon=  /26 rms-noise=10 -3 CCD rms-LOA=  /5 Focus image of a PD-pair True object (from 30 realizations) RESULTS Degraded Restored True
  • PART 1 Defining a method for in-flight calibration of IMaX aberrations a) Introduction b) Image restoration techniques d) Conclusions c) 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) Introduction b) Image restoration techniques d) Conclusions c) 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 IMaX The 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 2 Study 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 used for this study !!!
  • Outline Solar active regions Proper motions in a complex AR Moat flows surrounding sunspots Flow field around solar pores Conclusions PART 2 Study of proper motions in solar active regions
  • a) Solar active regions b) Proper motions in a complex AR d) Flow field around solar pores e) 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 regions b) Proper motions in a complex AR d) Flow field around solar pores e) Conclusions c) Moat flows surrounding sunspots PART 2 Study of proper motions in solar active regions Monolithic : Mag. field underneath the solar surface is Cowling, 1957 confined to a single flux tube. 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
  • a) Solar active regions PART 2 Study of proper motions in solar active regions Umbra Coolest part of the sunspots ~ 3500 - 5000 K Strong Mag.F inhibits convection Vertical magnetic field; more inclined at umbra-penumbra boundary ~ 2000 - 3500 Gauss in average Energy radiation 20% photosphere Features (umbral dots, light bridges) Penumbra Filamentary 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 regions PART 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 regions PART 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 regions PART 2 Study of proper motions in solar active regions Moat flow (Meyer et al. 1974) Could be: Typical cell scale of up to 10 4 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.
  • Averaged horizontal velocities [m s -1 ] a) Solar active regions PART 2 Study of proper motions in solar active regions + Young spots ♢ Old Spots Sobotka & Roudier, 2007
  • d) Flow field around solar pores e) Conclusions c) Moat flows surrounding sunspots PART 2 Study of proper motions in solar active regions a) Solar active regions b) Proper motions in a complex solar AR Observations 1m - 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 regions b) 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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  • Moat No Moat Exploding granules dragged by 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
  • PART 2 Study of proper motions in solar active regions b) Proper motions in a complex solar AR General description of proper motions Flowmap [Mm] Neutral Lines Exploding granules SOUP magnetograms MOMFBD+PD Combining 1500 images SNR=200 Resolution: 0.2 “/pix
  • PART 2 Study of proper motions in solar active regions b) Proper motions in a complex solar AR Moats Low velocity threshold: 400 m/s V moats = 0.67 km/s V h > 0.4 km/s Moats are closely associated with the presence of a penumbra.
  • 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 pores e) 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 pores e) 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 1m - Solar Swedish Tower (SST) S 1 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 2006 1 2 3 4 5 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 observations SST 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 pores Study 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 observations HINODE 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 during 14 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 pores Study of proper motions in solar active regions Radial directions Inward (-) Outward (+)   t  r r  Pore center
  • d) Flow field around solar pores Study of proper motions in solar active regions Flow map Gradients Radial directions Cos  Mask
  • d) Flow field around solar pores Study of proper motions in solar active regions Results FOV Cos  In Out
  • d) Flow field around solar pores Study of proper motions in solar active regions Outflows display larger velocity magnitudes Inflows 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 vicinity are 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 pores c) 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 Conclusions PART 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 To all of you
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  • Seidel aberrations
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  • 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 observations HINODE 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 V h km/s PART 2 Study of proper motions in solar active regions c) Moat flows surrounding sunspots Threshold used when plotting velocities !!!
  • 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 System Observing System
  • 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 pores c) 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 pores Study of proper motions in solar active regions Radial directions Inward (-) Outward (+)   t  r  r Pore center
  • 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 expect cancellations 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 not detectable 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 ( i t - i r ) < 2.5% loss of contrast < 5% IMaX case
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