The force as a result of a moving charged particle through a magnetic field is perpendicular to the field apparently. Why should the magnetic field be perpendicular to the force created as a result. F.b=q(vXB) is the mathematical notation for this which accurately describes the world. But I cannot imagine why it would be impossible for math to describe the magnetic force instead in terms of a magnetic field that is parallel with it. So is the directionality of the magnetic field, simply just assigned by definition, or does it have some basis in reality that can actually be proven by experiment?