The Loss Cone

The range of velocities through which a mirror leaks — and why plugs are needed.

Meaning

Escaping velocity range

In a magnetic mirror, particles whose velocity is too aligned with the field are not reflected and escape through the 'loss cone'. Refilling and plugging the loss cone is the central mirror challenge, which the tandem-mirror ambipolar plug addresses.

It is the physics behind the burner's plug-density requirement.