Fast-Ion Trackers
Fast-ion diagnostics track the energetic ions that carry fusion and heating power, essential for the burner's D-3He physics and the breeder's heating.
The energetic population
Fusion and auxiliary heating create a population of energetic ions well above the thermal bulk. Their confinement, slowing-down, and losses shape performance and can drive instabilities. Fast-ion trackers — neutral-particle and loss diagnostics among them — measure this population, giving the fabric a window the bulk diagnostics miss.
Why it matters more for the burner
The burner runs D-3He, whose fusion power is carried largely by charged products rather than neutrons (neutron fraction just 5.44%). The energetic-ion population and its confinement in the tandem mirror are therefore central to the machine's operation and to the direct energy conversion that follows. Fast-ion telemetry is a primary, not auxiliary, diagnostic here.
Into the fabric
- Fast-ion loss signals become precursor features for confinement degradation.
- Energetic-ion pressure enters the total pressure the MHD stability check uses.
- Losses to the wall couple to structural-health and thermal telemetry.
- Signals feed the twin modules that model the DEC train's incoming particle flux.
Breeder role
On the breeder, fast-ion trackers monitor the heating-ion population and any fast-ion-driven modes that could degrade confinement at 9.66 MA. The diagnostic family and its feature interfaces are shared across machines; the deployment weight and specific instruments differ, reflecting how much each machine's physics lives in the energetic population. Configurations are versioned per machine.