Tokamak vs Stellarator
Tokamaks use a plasma current for higher performance but risk disruptions; stellarators are disruption-free but complex. Kronos chose the tokamak and engineers around the disruption risk.
- Tokamak
- Plasma current + coils; higher performance; disruption risk
- Stellarator
- 3D coils, no current; disruption-free; complex
- Kronos choice
- Tokamak (spherical, high-field)
- Mitigation
- NT ELM-free edge, RWM feedback, vertical control
The two leading magnetic-confinement devices make opposite bargains. A tokamak drives a current through the plasma to help confine it — simpler coils and higher performance density, but that current can drive disruptions. A stellarator produces its entire field from intricate 3D external coils and needs no plasma current, so it is inherently steady and disruption-free — at the cost of far harder engineering and, historically, lower confinement.
| Dimension | Tokamak / Stellarator |
|---|---|
| Plasma current | Required (tokamak) / none (stellarator) |
| Disruptions | A risk to manage / essentially absent |
| Coil complexity | Simpler, planar-ish / complex 3D |
| Performance density | Higher / historically lower |
Kronos chose the tokamak for its higher performance density, and engineers around the disruption problem with a negative-triangularity ELM-free edge, strong vertical control, and RWM feedback.