Organization and Evolution of Solar Magnetic Field Serena Criscuoli INAF,OAR In Collaboration with Ilaria Ermolli, Mauro Centrone, Fabrizio Giorgi and April, 16, 2008 Mark Rast-LASP-Co,USA Dewey Anderson-LASP-Co,USA

Photometric properties of magnetic structures: comparison of models with observations Unruh et al, 2000, SSR Symbols: measurements Lines: models Ermolli, Criscuoli, Centrone, Giorgi 2007, A&A,

Criscuoli, Rast, Ermolli, Centrone 2007, A&A Complexity of magnetic structures Meunier, 2004, A&A MDI Magnetogram

SST, LaPalma, r=0.1” r=2”

SST La Palma 0.1” May, 20, 2004 Hirzberger & Wiehr, A&A, 2005

The Flux Tube Model (Spruit,1976) Steiner,A&A,2005

Still several open questions Big variety of contrast profiles (some don’t match with theory) Variation of contrast with position on solar disk Variation of size with position on solar disk Formation: emersion or coalescence? Do magnetic elements drive horizontal motions? Correspondence between high magnetic flux concentration and brightness enhancement Measured and simulated contrasts in G-band don’t match Clustering? Resolution? Selection?

Numerical Simulations of clusters of fluxtubes Plane parallel atmosphere 3D slab, infinite in one direction (y) atmosphere that varies in two directions (x,z) radiation + convection LTE + Radiative Equilibrium Intensity radiation field in the domain at different LOS Atmospheric model inside and outside the tube (iterative scheme)

P O M Radiation field: The Short Characteristic S,k and ρ are known on the grid s: space K: opacity ρ: density Formal solution to the radiative transfer problem for a given direction M  s i-1 O=s i P=s i+1 M

Temperature Field Criscuoli, 2008 Contrast profiles Beyond a Critical angle, single tubes are not resolved. Continuous: isotherms(˚K) Dotted: τ =1 lines at different LOS

Berger et al., ApJ,2007 o Where is the dark lane? (single small tube does not explain the measured size) o Asymmetries? ONE THREE r=0.1” Simulated Contrast profiles

Auffret&Muller,A&A,1991 Berger et al.,ApJ,2007 High Resolution measurements show centerward peak Hirzberger&Wiehr,A&A,2005 High Resolution measurements show (almost) no trend at the limb CLV of contrast

Contrast r=0.1” r=0.3” r=0.6” r=0.1” Clustering and selection flatten CLV of contrast at the limb Reduction of Resolution shifts peaks toward the limb

Still several open questions Large variety of measured contrast profiles Variation of contrast with position on solar disk Variation of size with position on solar disk Formation: emersion or coalescence? Do magnetic elements drive horizontal motions? Correspondence between high magnetic flux concentration and brightness enhancement Measured and simulated contrasts in G-band don’t match Coupling the RT code with HD existing code (M.Rast & D. Anderson-LASP) Analysis of high resolution narrow band images WORK in progress

DUNN SOLAR TELESCOPE High spatial resolution: 0.25” diffraction limit (AO system) High spectral resolution: 10mÅ High Cadence: 50 spectral lines in 30 secs. Spectro-polarimetric mode (2D!!!!) 1 Campaign: November 2007 (spectral mode) In collaboration with D.DelMoro (TorVergata University) A.Tritschler (NSO, USA) Arcetri Observatory Solar Group IBIS data reduction

Original Restored White Light