Alfvén Eigenmodes (TAEs)
Fast fusion ions can excite Alfvén-wave instabilities that expel them before they heat the plasma. Kronos flags TAE transport as a named open channel.
- What
- Alfvén waves driven unstable by fast ions
- Risk
- Expels energetic ions before they thermalize
- Kronos driver
- β_fast = 1.59% (S67)
- Status
- Named open channel
Toroidal Alfvén eigenmodes (TAEs) are plasma waves that the energetic ions produced by fusion and heating can drive unstable. When they grow, they can transport those fast ions out of the core before the ions deposit their energy — undermining both self-heating and the hot-ion posture.
Kronos MetroVolt carries a fast-ion pressure fraction of β_fast = 1.59%, enough that TAE-driven transport is flagged explicitly as a named open channel (analysis S67, extending the Alfvén-stability work S29). It is one of the design's ranked open items — not a showstopper, but a real physics question that the fast-ion behaviour and the channeling demonstration must resolve.