A

David

Darling

magnetic field lines

magnetic field of a bar magnet

Magnetic field lines are imaginary lines in space, used for visually representing the strength and direction of magnetic fields. At any point in space, the local field line points in the direction of the magnetic force which an isolated magnetic pole at that point would experience. In a plasma, magnetic field lines also guide the motion of ions and electrons, and direct the flow of some electric currents.