Comparisons of the main current sheet region in Cases 3 (top panels) and 5 (bottom panels) at the times when the plasmoid instability is well developed. The distributions of temperature (panels a and b), density (panels c and d), vertical velocity V_y (panels d and f) are shown, along with the synthetic Si IV 1394 Å line emission at each grid point (panels g and h). The black arrows in panels e and f represent the total velocity. The background magnetic fields are 500 G and 600 G in Cases 3 and 5, respectively. The amount of emerging flux in Case 5 is greater than that in Case 3. The heat conduction and ambipolar diffusion effects are not included in Case 5. Panels g and h are shown in arbitrary units.