Electron energy distributions for different simulations, considering the variation in specific parameters: the mass ratio, m_i/m_e, in panel a; the simulation domain size, L_x × L_y, in panel b; and the initial temperature ratio, T_0, i/T_0, e, in panel c. The dashed lines show the initial energy distributions and the solid lines represent the distributions at $t=90{\mathrm{\Omega }}_{0,i}^{-1}$.