The Magnetic Mirror's Second Life

Why an old idea, reworked with modern magnets and physics, is compelling again.

Magnetic mirrors were among the earliest fusion concepts but fell behind tokamaks when simple mirrors proved leaky and unstable. Decades of physics — minimum-B stabilisation, the tandem-mirror plug, thermal barriers — solved the core problems, and modern high-field superconductors make the required plug fields attainable.

The Kronos burner is a modern tandem mirror: low-neutron D–³He, direct conversion, no disruptions — with the plug-density requirement (n_p/n_c ≈ 16) as its honest open item.