Gyrokinetic Turbulence

Gyrokinetics models the small-scale turbulence that drains heat from a plasma. The nonlinear gyrokinetic check on Kronos confinement is the outstanding verification.

What

First-principles model of plasma micro-turbulence

Governs

Turbulent heat and particle transport

Reduced model

TGLF (S16/S18) — indicative only

Load-bearing

Nonlinear CGYRO/GYRO — outstanding

Gyrokinetics is the physics of the small-scale turbulence that dominates how heat leaks out of a fusion plasma. Rather than track every particle's fast gyration, it averages over that motion to compute the drift-wave turbulence that sets the turbulent transport — and therefore the energy confinement time.

For Kronos MetroVolt this is the crux of the confinement case. The required H98 = 1.84 assumes that negative triangularity suppresses this turbulence, but that assumption has only been checked so far with the reduced quasilinear model TGLF (S16/S18) and the DIII-D database. The load-bearing verification is a nonlinear gyrokinetic study (CGYRO/GYRO), which remains outstanding and is the first thing the G1 testbed exists to measure.