view out of the THEMIS telescope dome (Tenerife) Solar Surface Anisotropy effect on the Magnetic Field Véronique Bommier LESIA, Observatoire de Paris IAU Symposium 305 Punta Leona (Costa Rica), 30 November-5 December 2014
NOAA 10953 VECTOR MAGNETIC FIELD MAPS Hinode 1 May 2007 2 lines: Fe I 6301.5 and 6302.5 Å independent ME inversion (UNNOFIT code, Bommier et al. 2007) vector current density lines of the same multiplet: constant Δ H (simulation quiet Sun & AR by Khomenko & Collados 2007) formation depth difference: 98 km ambiguity removed by |div B |+| J z | minimization (DIVB2, modified ME0 code of Leka et al., simulated annealing) vector Lorentz force 119 maps available 96 THEMIS 2010-2013 campaigns & 23 HINODE http://lesia.obspm.fr/perso/veronique-bommier Véronique Bommier's homepage
Fe I 6301.5 Å and 6302.5 Å are 2 lines of the same multiplet 816 parallelism from Khomenko, E., & Collados, M., 2007, ApJ 659, 1726 Direct measurement of ∆ h by phase shift method (cross-spectral analysis): quiet Sun, HINODE data: ∆ h = 63.2 ± 0.9 km (Faurobert et al., 2009, A&A 507, L29) confirmed by 3D simulations of solar magneto-convection: ∆ h = 69 km Stein & Nordlund's + Uitenbroek's codes (Grec et al., 2009, A&A 514, A91)
THEMIS observation of a plot of plot of double sunspot ( δ -spot) B X X B Y Y B Z Z 10 B X X 10 B Y Y B Z Z on 13 September 2005 MULTILINE divB divB scaled by the aspect ratio color scale: scaled to the measurement inaccuracy level (including inversion)
vertical gradient dBz/dz: 3 G/km horizontal gradient dBx/dx+dBy/dy: 0.3 G/km • Westendorp Plaza et al., 2001, ApJ 547, 1130 • Balthasar, 2006, A&A 449, 1169 2 lines Fe I 6301.5 & 6302.5 Å 3 lines Fe I 15648, 15452 & 10896 Å observed with ASP (Sac Peak) observed with the TIP mounted on the VTT (Tenerife) SIR inversion, provides also d/dz 8 sunspots result: 1.5-2 G/km ( 4 G/km in a previous analysis) SIR inversion result: 0.5 G/km • Balthasar & Schmidt, 1993, A&A 279, 243 3 lines Fe I 6302.5 & 6842.7 Å & Fe II 6149.2 Å • Hagyard et al., 1983, Sol. Phys. 84, 13 spectropolarimetry with the VTT (Izaña, Tenerife) 1 highly sensitive line Fe I 5250.2 Å inversion by comparison with theoretical profiles MSFC magnetograph (Hunstville, Alabama) by Grossmann-Doerth et al. (1988), G-D (1994) 1 sunspot Unno-Rachkovsky sol. in a model atmosphere result: 0.1-0.3 G/km d/dz is derived result: 2.5 to 3 G/km • suppose a regular sunspot diameter 10,000 km suppose that Bx varies from • Pahlke & Wiehr, 1990, A&A 228, 246 –1500 G to + 1500 G 6 lines Si I 6142.9, Zr I 6143.2, Fe II 6149.2, from one penumbra side to the other penumbra side Ti I 6149.7, Fe I 6151.6, Na I 6154.2 Å the mean horizontal gradient results into 0.3 G/km circular polarization models observed with the Gregory-Coudé telescope (Tenerife) direct field measurement in umbra by Zeeman splitting • Eibe, Aulanier, Faurobert, Mein, Malherbe, 2002, best agreement between the 6 lines if A&A 381, 290, report a factor of 10 between a gradient of 2 G/km is assumed. • observations : longitudinal field Na I D1 observed with THEMIS/MSDP • Bruls, Solanki, Rutten & Carlsson, 1995, A&A 293, 225 depth probing along the highly resolved line profile reanalyze FTS (Kitt Peak) observations by via response functions computed with the MULTI code Hewagama et al. (1993) (Carlsson 1986) 2 infrared lines Mg I 12.22 & 12.32 m • theory : force-free extrapolation (Démoulin, Bagala, (formed in the upper photosphere) Mandrini, Hénoux, Rovira, 1997, A&A 325, 305) MULTI code (non-LTE multilevel, Carlsson 1986) + DELO Stokes profile synthesis • Pizzo, 1986, ApJ 302, 785 (Rees et al., 1989, Murphy, 1990, Murphy & Rees, 1990) magnetostatic equilibrium modelling (not force-free) result: 2-3 G/km result: 0.2-0.4 G/km (Fig. 15, for large tube radii that model sunspots)
This cannot be ascribed to the lack of resolution Demonstration in the spatial Fourier space real space Fourier transform spatial Fourier space ˆ e i k x x f ( x )d x f ( k x ) f ( x ) derivation: multiplication: k x ˆ x f ( x ) f ( k x ) filtering: convolution product normal product ˆ ( k x ) ˆ F ( k x ) ˆ F ( x ) ( x x ) f ( x )d f ( k x ) x
What is measured: H or B ? I
What is measured: H or B ? II
Anisotropic Debye shielding (local dynamo) Open Access paper by Bommier in Physics Research International http://www.hindawi.com/journals/physri/2013/195403/ + Bommier, 2014, Comptes Rendus Physique, 15, 430 (available from the ADS)
The photosphere: a strongly stratified medium viscosity-affected From Brethouwer, Billant, Lindborg, Chomaz, J. of Fluid Mechanics, 585, 343: h 0.02 1 The horizontal Froude number in the photosphere is found F the photosphere is a strongly stratified medium (not the solar Corona, having F h 3) 2 0.1 1 The Reynolds number is R e 500 1, but the buoyancy Reynolds number is R b R e F h the photosphere lies in the "viscosity-affected flow regime": no inertial cascade can develop the typical horizontal/vertical length ratio ("aspect ratio") is R e 20 the horizontal/vertical velocities and then Debye lengths are different: anisotropy Temporary conclusion
An experimental proof ? Physical conditions of the experiment taken from Van Compernolle, Bortnik, Pribyl, Gekelman, et al., 2014,Phys. Rev. Letters 112, 145006 Description of the experiment in Gekelman et al., 1991, Rev. Sci. Instrum. 62, 2875
NOAA 10808 observed on 13 September 2005 with THEMIS THEMIS
NOAA 10808 observed on 13 September 2005 with THEMIS magnetic field vector THEMIS
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