How the Burner Works: A Primer
The burner (Aegis / MetroVolt) is a D-3He tandem-mirror generator that converts charged-particle energy directly to electricity, with a small neutron fraction and severe open gates.
A tandem-mirror, not a tokamak
The breeder (Hyperion) is a D–T spherical tokamak. The burner is a different machine: a D–3He tandem mirror. Deuterium fuses with helium-3, a reaction whose primary products are charged particles rather than neutrons, which is why the design targets direct energy conversion — capturing the kinetic energy of charged products as electricity instead of boiling water.
Design magnetics
The tandem mirror confines plasma between high-field plugs. The studied design point uses a 26.49 T plug field and a 17 T throat field. The neutron fraction is 5.44% — small compared with a D–T machine, but not zero, so shielding and activation still matter.
- Plug field: 26.49 T
- Throat field: 17 T
- Neutron fraction: 5.44% of fusion energy
- Conversion: direct energy conversion of charged products
Why the primer ends with gates
The same design point that produces this energy path also produces the four open gates. The plug coil is overstressed ~3–3.9× at the design bore; the plug regime is 166–830× beyond any device operated to date; helium-3 demand exceeds domestic supply by ~400× per commercial unit; and availability sits at 0.86–0.995. A primer that omitted these would misrepresent the machine. The burner is a promising study with real, named obstacles.
Why this machine, despite the gates
The reasons to study a D–3He tandem mirror for defense power are the small neutron fraction, direct energy conversion, and a fuel that can in principle be bred sovereignly. Those merits are why the gates are worth the effort rather than reasons to abandon the concept. A primer's job is to hold both in view: a machine with genuine advantages for fixed installations and with four quantified obstacles that no honest description omits.