Magnetic Field Strength and Inclination in the Penumbral Fine-Structure
  The uncertainty about a possible correlation between strength and inclination of the magnetic field and the continuum intensity of the sunspot penumbral fine-structure has been removed by a detailed analysis of a spatially very high resolved spectrum: the darker, lengthy penumbral lanes host a 10% stronger and >30 deg flatter magnetic field as compared to the bright penumbral locations. This finding does not only result from the high spatial resolution but also from the choice of the Fe I 6842.7 line, which obtains its essential contribution from those deep layers near the continuum intensity level where the penumbral structure is seen. The almost perfect correlation establishes that the penumbral structure is formed by two magnetic components mainly differing by their field inclination. The discrepancy with results from other Zeeman lines, as e.g. Fe I 6302.5, indicates a different field structure above the white light penumbral layers. 
E. Wiehr
astro-ph.SR