Fig. (5) Distribution of φ in the characteristic positions for the displacement at λ = 1.45 mm and the maximum distance for the propagation = 4.35 mm. (a-e) show the distributions of φ at the following characteristic positions, z_t, z_φ1, z_r, z_φ2 and z_rl. The area fraction of φ, from 45° to 90°, for all the computation results is indicated in (f).