Snapshot of ch024031_by200bz005 at t = 40 min. Top: temperature structure in a vertical cut through the computational domain at Y  =  19 Mm (indicated with a dashed line in the lower panel). The plasma β equal to one surface is highlighted with a thin dashed line. Bottom: vertical velocity at the photosphere (Z  =  0 Mm). The strongest magnetic field enhancements are highlighted by polarity (purple = negative and green = positive). The field at the photosphere is mostly negative and contained in the intergranular lanes. Data are shown from the same snapshot as Fig. 2.