X–Z (left) and X–Y (right) slices. Top row: density; middle row: charge density; bottom row: plasma sigma ﹩\sigma ={\omega }_{B}^{2}/{\omega }_{p}^{2}﹩. Slight asymmetry in the X–Y-plane is likely due to mild left–right instability of the flow. Nonnegligible charge density within the Alfvén wings is specific to the relativistic regime.