Simulations L1 (top) and WT1 (bottom) at t = 1.59. The plots on the left-hand side show the temperature distribution in a horizontal plane just below the upper surface of the computational domain (shaded contours) and the distribution of B_z in the same horizontal plane (black and white contours). The volume renderings on the right-hand side of this figure show isosurfaces of |B| = 0.25. Some fieldlines have also been traced out along these isosurfaces in order to aid visualisation.