Temperature in the plane perpendicular to the z axis at position z = 0. The temperature was measured for the case without thermal conduction. The colour scale gives white as the initial temperature and dark as max(T) = 2.55 × 10^-2 (dimensional temperature 367.42 MK), which is obtained at time 105. The dotted line in Fig. 3 shows the data along a cut through the centre of the plane along the x direction.