Force-free magnetic fields

This article reviews the subject of force-free magnetic fields. It critically analyzes the force-free condition, explaining that it behaves properly under Lorentz, parity, rotational, and time-reversal transformations. It refutes the proof that it is impossible to have completely force-free magnetic fields. It shows how general solutions of the force-free condition in rectangular, cylindrical, and spherical coordinate systems are obtained. It explains how these fields have been applied in different areas of physics.