High-Harmonic Fast Wave (HHFW)

HHFW is a radio-frequency method for heating and driving current in spherical tokamaks — and the launcher Kronos proposes for the fast-ion channeling test.

What

A fast magnetosonic wave at high cyclotron harmonics

Uses

Heating and current drive in STs

Kronos role

Proposed launcher for fast-ion channeling (P6)

Regime

Well matched to spherical-tokamak conditions

The high-harmonic fast wave (HHFW) is a radio-frequency technique that launches a fast magnetosonic wave at high harmonics of the ion cyclotron frequency, well matched to the low-field, high-density conditions of a spherical tokamak. It can both heat the plasma and drive non-inductive current.

For Kronos MetroVolt, HHFW has a second, specific role: it is the launcher proposed to demonstrate fast-ion channeling (prediction P6) at the G1 testbed — using the wave to redirect fast-ion energy into the fuel ions. HHFW is thus part of both the routine heating toolkit and the specific experiment that would test one of the design's key upsides.