plasma thermal properties; consequently, we use a simple adiabatic energy equation and numerical resistivity. Our simulations do not include effects such as thermal conduction, or radiative transfer, or a generalized Ohm’s law with Hall and ambipolar-diffusion. These effects are well known to be important in the real corona and chromosphere for determining the plasma energetics [see e.g., @MartinezSykora12; @Leake13a; @Leake14b]. Additionally, our simulations assume strict line-tying conditions at the lower boundary. The primary challenge in numerical simulation of solar jets, however is not the plasma thermodynamics, but the effective Lundquist number of the simulation. Even in the chromosphere the Lundquist number is high, $> 10^6$ or so, well beyond the reach of present 3D simulations. It is absolutely essential that the numerical Lundquist number be as high as possible so that the resulting evolution is determined by true helicity-conserving reconnection rather than by simple diffusion. Our adaptive mesh refinement code [*ARMS*]{} does an excellent job at conserving helicity, even for reconnection-dominated evolutions [e.g., @Knizhnik15; @Pariat15b].

    $\beta$      $L_0 $     $t_0$     $B_0$       $P_0$             $\rho_0$                   $T_0$                   $V_0$            $c_A$      $c_S$            $E_0$               Solar layer
  ------------ ---------- --------- --------- ------------- ------------------------- ----------------------- ----------------------- ---------- --------- ------------------------ -------------------
    $ 1.0 $     $ 0.05 $   $ 1.1 $    