Fig. S5.

Effect of radiative cooling in the interaction region of the colliding jets experiment. The top half of the image shows $T_e$ in the interaction region at t = 1 µs in a FLASH simulation of the colliding jets experiment in which multigroup radiation diffusion (and therefore radiative cooling) was turned off at $t=716$ ns (i.e., just before the two jets collide). The bottom half of the image shows the same, except multigroup radiation diffusion was on throughout. Comparison of the two images shows $T_e$ is a factor of $\sim$ 3 larger in the first case, demonstrating that radiative cooling is very important in the interaction region.