Recent Advances in the Exploration of the Small-Scale Structure of the Quiet Solar Atmosphere: Vortex Flows, the Horizontal Magnetic Field, and the Stokes-V Line-Ratio Method

摘要

We review (i) observations and numerical simulations of vortical flows in thesolar atmosphere and (ii) measurements of the horizontal magnetic field inquiet Sun regions. First, we discuss various manifestations of vortical flowsand emphasize the role of magnetic fields in mediating swirling motion creatednear the solar surface to the higher layers of the photosphere and to thechromosphere. We reexamine existing simulation runs of solar surfacemagnetoconvection with regard to vortical flows and compare to previouslyobtained results. Second, we review contradictory results and problemsassociated with measuring the angular distribution of the magnetic field inquiet Sun regions. Furthermore, we review the Stokes-V-amplitude ratio methodfor the lines Fe I 630.15 and 630.25 nm. We come to the conclusion that therecently discovered two distinct populations in scatter plots of this ratiomust not bee interpreted in terms of 'uncollapsed' and 'collapsed' fields butthey stem from weak granular magnetic fields and weak canopy fields located atthe boundaries between granules and the intergranular space. Based on newsimulation runs, we reaffirm earlier findings of a predominance of thehorizontal field components over the vertical one, particularly in the upperphotosphere and at the base of the chromosphere.