Horizontally and temporally averaged values of the vertical Poynting flux in the solar atmosphere. The top panel shows its stratification in the photosphere and low chromosphere and the bottom panel displays its behaviour in the chromosphere and above on an expanded vertical scale. The blue line shows the shear (wave) −B_z(v_xB_x + v_yB_y), the red line the flux advection v_zB_h², and the black line the total vertical Poynting flux. The solid lines show the mean value and the shaded area shows two standard deviations.