Radial variation in magnetic field strength and LOS velocity. Top: radial variation of the field strength in flow channel (thick grey) and background field (thin black). The difference between them is plotted in the lower half. Bottom: horizontal and vertical velocities for background field and flow channel component from the fit of a sinusoidal to the azimuthal variation of v_LOS. Black: background field, red: flow channel component. Dashed: vertical velocity, solid: horizontal velocity.