KE spectrum. Snapshots of the KE (u²/2 + v²/2) spectra from simulations with ε = 2.9 × 10⁻¹¹ and μ = 10⁻⁷. The blue line shows the simulated KE spectrum. The green, red, and black dashed lines indicate the theoretical slopes of −3, −5/3, and −5, respectively. The transition wavenumbers n_e, n_β, and n_Rh are also marked, where n_β and n_Rh are estimated using the averaged β across the domain.