Neutral Beam Injection (NBI)

NBI fires fast neutral atoms into the plasma to heat it, drive current, and set rotation — a workhorse tool with multiple roles in the Kronos design.

What

Injecting a beam of fast neutral atoms

Roles

Heating, current drive, rotation, fuelling

Byproduct

A fast-ion population

Related

Rotation feeds flow-shear turbulence suppression

Neutral beam injection (NBI) is a workhorse of tokamak heating: a beam of fast neutral atoms is fired into the plasma, where they ionize and transfer their energy to the plasma particles. Because they enter neutral, the beams cross the magnetic field freely before ionizing deep in the core, depositing energy where it is most useful.

NBI does several jobs at once for a machine like Kronos MetroVolt: it heats the plasma, drives non-inductive current, imparts torque that sets rotation and beneficial flow shear, and can fuel the core. It also creates a population of fast ions whose behaviour — confinement, channeling, and possible TAE drive — is one of the design's active research areas.