  Three-dimensional topological textures have become a topic of intense
interest in recent years. Through analytical calculations, this work determines
the magnetostatic field produced by a Bloch Point (BP) singularity confined in
a magnetic nanosphere. It is observed that BPs hosted in a nanosphere generate
magnetic fields with quadrupolar nature. This finding is interesting because it
shows the possibility of obtaining quadrupole magnetic fields with just one
magnetic particle, unlike other propositions considering arrays of magnetic
elements to generate this kind of field. The obtained magnetostatic field
allows us to determine the interaction between two BPs as a function of the
relative orientation of their polarities and the distance between them. It is
shown that depending on the rotation of one BP related to the other, the
magnetostatic interaction varies in strength and character, being attractive or
repulsive. The obtained results reveal that the BP interaction has a complex
behavior beyond topological charge-mediated interaction.
