Histograms of various quantities in swirling regions for three layers of 210   km width each, centered at heights z =  −630   km, z = 0   km, and z = 630   km. Solid lines represent the magnetic case, dashed lines the non-magnetic case. The quantities considered are swirling period (upper left panel), gas pressure normalized to its horizontal average (upper right), temperature normalized to its horizontal average (lower left), and vertical velocity component (lower right). Each histogram is normalized by its integral.