Surface appearance of the vertical magnetic field, , in the ILES simulations with different Mach numbers (top to bottom). The color coding shows in the range of − 0.1 (white) to + 1.0 (black). Root-mean-square Mach numbers are given by the labels. For the upper two rows with lower Mach number, the left column is for fixed initial mean field, whereas in the right column the initial field is adjusted between the runs, such that the field strength remains constant relative to the kinetic energy in the background turbulence.