Cartoon illustrating the model adopted for the deflection in a magnetic field for an individual bullet of mass m_b and radius r_b. The bullets which create the shocks are assumed to experience an excess magnetic pressure such that B_outer  ≥  B_inner (top left). The bullets move with a velocity v_b along a curved path due to the excess magnetic pressure which they thereby feel (bottom left). The figure bottom right shows the displacement in the plane of the sky, s, of a bullet between that arising from a rectilinear motion in the absence of a net magnetic pressure and the curved path in the presence of a magnetic pressure. The angle θ, see the derivation of Eq. (2), is also illustrated.