(a) Evolution of v_θ for t₀ = 0.8 corresponding to a super-Alfvénic flow and critical points inside the thread. The initial pulse has a width of l = 0.6 and the evolution of the pulse is shown up to t = 18 when it approaches the critical points at about ±0.4. (b) Evolution of b_θ for a 0.6 wide pulse up to t = 18 showing the pulse propagating to the critical points at about ±0.4. (c) The corresponding total energy of the system, up to t = 18. (d) The total magnetic flux up to t = 18 showing no variation until t = 18.