The dimensionless α parameter (volume averaged in cylindrical annuli described in the main text) for the ﹩{\rm{\Delta }}x\simeq 175\,\mathrm{km}﹩ models at two initial field strengths, B₀ ≃ 1 kG (blue, bold) and B₀ ≃ 1 μG (blue, fine). For the kilogauss run, we also show contributions to α from Maxwell stresses ﹩{\alpha }_{M}=\langle {T}_{M,R\phi }\rangle /\langle {P}_{g}\rangle ﹩ (orange) and Reynolds stresses ﹩{\alpha }_{R}=\langle {T}_{R,R\phi }\rangle /\langle {P}_{g}\rangle ﹩ (green).