The left panel shows the v_z map at t = 701 s with a curved slit S₃, starting from right to left along the path of the propagating Alfvén wave packet. The independent points a (yellow), b (blue), c (green), d (red), e (magenta), f (cyan), g (orange), h (purple), and i (gray) have been taken on the S₃ to understand the properties of v_z at different locations. Panels (a) and (b) are time–distance profiles of v_z and Δb_z = (B_z − 0.5)B^* along S₃. All the horizontal dotted lines on the time-distance profiles of v_z and Δb_z represent independent positions on S₃ as depicted in the left panel (the line colors kept the same as the colors of chosen points). Panels (c) and (d) represent the temporal profile of v_z and Δb_z at those points, and both v_z and Δb_z are in the same phase and in agreement with the properties of the Alfvén waves.