One of the key research problems in stellar physics is to decipher the small-scale magnetic activity of the quiet solar atmosphere .
Recent magneto-convection simulations that account for small-scale dynamo action have provided three-dimensional ( 3D ) models of the solar photosphere characterized by a high degree of small-scale magnetic activity , similar to that found through theoretical interpretation of the scattering polarization observed in the Sr i 4607 Å line .
Here we present the results of a novel investigation of the Hanle effect in this resonance line , based on 3D radiative transfer calculations in a high-resolution magneto-convection model having most of the convection zone magnetized close to the equipartition and a surface mean field strength { \langle B \rangle } { \approx } 170 G. The Hanle effect produced by the model ’ s magnetic field depolarizes the zero-field scattering polarization signals significantly , to the extent that the center-to-limb variation of the calculated spatially-averaged polarization amplitudes is compatible with the observations .
The standard deviation of the horizontal fluctuations of the calculated scattering polarization signals is very sensitive to the model ’ s magnetic field and we find that the predicted spatial variations are sufficiently sizable so as to be able to detect them , especially with the next generation of solar telescopes .
We find that at all on-disk positions the theoretical scattering polarization signals are anti-correlated with the continuum intensity .
To facilitate reaching new observational breakthroughs , we show how the theoretically predicted polarization signals and spatial variations are modified when deteriorating the signal-to-noise ratio and the spectral and spatial resolutions of the simulated observations .