[shpeedy]

So, EM field describes strength of EM force in every point of mathematical model. Nature of EM force is unknown. Right?

Let's talk about nature of EM force.

Analogy: look at a typical tropical cyclone. It rotates. Is it rotating because a unknown property of an air molecule? No. It rotates because our planet rotates, while air molecules are just trying to keep their positions. I.e. it's rotation of planet + inertia of molecules.

Is it possible that EM force is happens because our local space is moving trough global space by non-linear trajectory, so it just non-linear trajectory of local space + inertia of rotating and vibrating particles?