The integral of the magnetic flux through a closed surface must be identically zero from Gauss' law for magnetism. If you draw a box anywhere in space, the magnetic flux entering it and exiting it must be equal.
Look at the attached crudely edited image of your plot, everywhere on the square surface outlined in the center the magnetic flux is pointing outwards. This violates Gauss' law and would require a magnetic mono-pole. The B-field should enter through the flat faces of the box and leave through the corners (or vice versa). To prove me wrong, you'll have to show me some flux passing from the outside of the box to its interior to balance the obvious flux passing from the interior towards the outside in order to satisfy Gauss.
- H87p73L.png (199.52 KiB) Viewed 10882 times
Also attached is a quick plot i made with a commercial 3D modeler. No symmetry planes are used. Shown is a midplane slice where color represents the magnitude of B, the black vectors are normalized and not dependent on field magnitude, and the white streamlines are just for further illustration. Notice it is divergence free everywhere and B goes to zero with an undefined direction at the origin.
- Bfield2.png (220.88 KiB) Viewed 10872 times