On the Origin of Solar Faculae

Abstract

Solar faculae appear as bright small features close to the solar limb. Recent high-resolution images show these brightenings in unprecedented detail. Our analysis of numerical MHD simulations reproduces the observed small-scale features. The simulations reveal that faculae originate from a thin layer within granules just below largely transparent magnetic flux concentrations. This is basically the "bright wall" model of Spruit. The dark, narrow lanes often associated with faculae occur at the opposite side of the magnetic flux concentration and are due to an extended layer with lower-than-average temperature.