Sod shock tube experiment with CR acceleration efficiency of η = 0.5, zero initial CR pressure and γ_CR = 4∕3 at t = 0.35. Left panels: solution over the full box. Right panels: zoomed-in region over the shock and contact discontinuities for better clarity of the CR shock-accelerated region. From top to bottom: pressures (black: total, blue: thermal, red: CR), the density, the velocity, the Mach number, the effective adiabatic index, and the level of refinement. The symbols stand for the numerical solution, while the solid lines are forthe analytical solution. The exact Sod solution with accelerated CRs is reproduced well by our numerical implementation.