17 T Throat Coil

The throat is the 17 T field maximum between each plug and the central cell; it anchors the mirror geometry the plug potential sits on.

Between each plug and the central cell the field rises to a maximum of 17 T at the throat. The throat is the magnetic pinch point — the mirror proper — where the field is strongest along the confinement path from cell to plug. Its ratio to the central-cell field sets the base magnetic mirror ratio before any electrostatic plugging is added.

The throat coil is a high-field magnet in its own right, though below the 26.49 T plug. It shapes the transition from the uniform central-cell field up to the plug region, and its geometry determines the loss cone the plug potential must then close. Getting the throat field and profile right is what makes the plug's electrostatic barrier effective.

Role in the confinement chain

• Sets the field maximum (17 T) between plug and central cell
• Defines the base magnetic mirror ratio
• Shapes the loss cone the plug potential must plug
• Anchors the axial field transition on both ends
• Carries high magnetic load, below the plug but well above the cell

Throat and plug together

The throat and plug are a matched pair. The 17 T throat sets the mirror; the 26.49 T plug builds the potential atop it. Neither alone confines the central cell — the magnetic mirror leaks through the loss cone, and the electrostatic barrier needs the mirror geometry to sit on. The two fields, 17 T and 26.49 T, are the two numbers that define the end-confinement of the burner.

All figures are design-and-simulation values for a machine not yet built.