Plasma Current 9.66 MA

The design plasma current of 9.66 MA sets the confinement and stability the breeder needs to reach its gain point.

Why current matters

Plasma current is one of the primary levers on tokamak performance. It sets much of the confinement and helps hold the plasma stable. The breeder is designed for a plasma current of 9.66 MA, chosen together with the field and shape to reach Q_sci 3.076.

Current, confinement, and gain

Energy confinement in a tokamak scales strongly with plasma current, so 9.66 MA is a large part of why the compact machine can hold enough energy to reach gain. The confinement gate G1 tests whether the real machine, at 9.66 MA and full field, achieves the predicted confinement.

The engineering it demands

• A central solenoid and current-drive capability to establish and sustain 9.66 MA
• Stability control to manage a high-current compact plasma
• Structural design to handle the forces a large current implies

Interaction with the other design points

9.66 MA does not stand alone. It works with the 8 T on-axis field, the negative triangularity of -0.30, and the compact spherical geometry as one coherent operating point. Change one and the others must move. This is why the design point is quoted as a set, not as isolated numbers.

9.66 MA is a design value for a machine not yet built. First plasma will begin at far lower current, and the ramp to 9.66 MA is where confinement is measured against prediction at G1.