Magnetron TwinsElectromagnetism / Polarity Lock

The Magnetron Twins should not exist. According to classical physics, there are no magnets.

Feynman says so in Chapter 34 of the second volume of his Lectures: the magnetic effects of materials cannot be understood in any honest way from classical physics. A classical theorem shows that charges moving around in thermal equilibrium produce no net magnetism at all. Magnets are quantum objects.

The source is the electron itself. Besides any orbital motion, every electron carries an intrinsic angular momentum, spin, and with it a magnetic moment of about one Bohr magneton, 9.27 × 10⁻²⁴ joules per tesla. It is not a tiny charge spinning on an axis; it is simply a property the electron has. In iron, cobalt and nickel, a quantum effect called the exchange interaction makes neighbouring electron spins line up, and vast numbers of them pointing together make a fridge magnet. Most of the magnetism in ordinary matter comes from electron spin, not from charges circling in orbits.

The formula on this page is what two such magnets do to each other: the energy of two dipoles depends on their separation, falling as one over the cube of the distance, and on how each points relative to the line joining them. For the twins: placed nose to tail along the same line, pointing the same way, they attract. Placed side by side pointing the same way, they repel; flip one and they attract. The formula tracks every angle in between.

There are no single magnetic poles in this picture. Cut a magnet in half and you get two magnets, each with both ends. Nobody has ever found an isolated north pole.

The Magnetron Twins are always a pair. Physics has never offered either of them the alternative.