Donut With A Twist The fusion shape everyone quit on

The stellarator is the fusion shape everyone quit on. Too twisted to build, said the field in the 60s, and off it went to do tokamaks for the next 50 years. Then optimization software got good enough to solve the coil geometry, Greifswald spent a billion euros proving the physics holds, and now Proxima Fusion – Munich, spun out of Max Planck, 411 million euros richer since July – wants to turn it into a power plant. On a decommissioned fission site, because of course Germany.

Ben Miles walks the whole thing through: why a donut leaks, why the Soviets won in 1968, and why fusion output scaling with the fourth power of magnetic field is the closest physics gets to a cheat code. Triple the magnet, 81 times the power.

He’s an investor in Proxima and says so in minute one, which puts him ahead of most energy coverage this year.