The burner is a magnetic mirror, not a tokamak: its field lines are open, so charged particles stream out the ends by design. That leak is not a loss to be plugged; it is the power stream the direct converter harvests.
A mirror confines plasma along a straight central cell between two high-field throats. Particles energetic enough to escape the throat flow out along open field lines into an expander and a direct-conversion end tank. For a fuel like D-3He that releases its energy in charged particles, open ends are a feature: the exhaust is electricity waiting to be collected.
Open geometry is simpler to build and maintain than a closed torus, and it hands the D-3He cycle a natural path to direct conversion without a steam loop. The burner's architecture follows from its fuel.
| Geometry | open-ended magnetic mirror |
| Central cell | straight, between two throats |
| Exhaust | charged particles on open field lines |
| Harvest | expander + direct converter |
| Fuel fit | D-3He releases energy as charged particles |