Gas Injection & Fueling

Fueling delivers the deuterium and helium-3 mix into the central cell and trims composition to hold the operating point.

Fueling is the controlled delivery of fresh fuel into the plasma to sustain the burn and hold the target composition. In a steady-state tandem mirror, fueling replaces particles lost to the ends and to reactions, matching the recovery and pumping systems so density and mix stay on their setpoints.

Delivery methods

Fuel can be introduced as gas at the periphery or as pellets that penetrate deeper into the plasma. The method and location affect where fuel deposits and how the density profile builds. The fueling design targets a stable central-cell profile consistent with the plug confinement and the ambipolar potential.

Composition control

• Diagnostics measure density and the D-to-³He ratio
• Control adjusts injection to hold the operating point
• Interlocks bound the maximum fueling rate for safety
• Helium-3 use is minimized through recovery and recycle

Coupling to the burn

Fueling is one lever in the steady-state control loop that also involves heating, pumping, and plug operation. Together they hold the plasma at the design point. Fueling behavior is modeled at design stage against the frozen D-³He configuration; the machine is not yet built.