Growth rates of the MHD modes as a function of θ for a fixed value of δ = π/4 and k_x = π. The wave vector k is aligned with the x-axis. The thermal mode becomes unstable for θ >  π/4, at this point parallel thermal conduction is too ineffective for stabilisation due to the alignment between B₀ and k. The growth rate of the fast mode was multiplied by 50 for clarity. The equilibrium temperature is 0.50 MK; the density and magnetic field are the default values.