Evolution of the system for θ = 3° (left column), 10° (central column), and 20° (right column). The bottom boundary displays the distribution of B_z. The top row shows the initial configuration. The blue field lines are plotted at fixed intervals along x = 0 and z = 0 from fixed footpoints in the initially open domain. The white field lines are plotted from fixed footpoints along a circle of radius r = 3 and are initially closed. The middle row displays the system at t = 600 during the straight jet phase. Isosurfaces of the plasma density at ρ/ρ₀ = 1.05 are color shaded according to the vertical velocity v_z, showing the acceleration of plasma in the straight jet. The bottom row presents the system during the helical jet phase. Isosurfaces of the plasma density at ρ/ρ₀ = 1.2 are color shaded according to v_x: red and blue indicate plasma flow away from and toward the observer (similar to Dopplergrams), highlighting the strong rotation in the helical jet.