Time evolution of plasma energy density for a plasma initialized with e_i = 10²e_equi (cooling) and e_i = 10⁻²e_equi (heating). The red and blue dashed lines are the semi-analytical solutions for the cooling and heating cases, respectively. The black dashed line shows the equilibrium plasma thermal energy. Due to the logarithmic scaling of the time axis, the initial conditions at t = 0 are not seen here.