Quantum mechanics

Magnetic field

Turbulence

Computational physics

Nuclear physics

Wendelstein 7-X

Magnetic confinement fusion

Atomic physics

Plasma

Electric field

Gyrokinetics

Physics

Electron temperature

Ambipolar diffusion

Stellarator

Tokamak

Mechanics

Physical Review Letters

We theoretically assess two mechanisms thought to be responsible for the enhanced performance observed in plasma discharges of the Wendelstein 7-X stellarator experiment fueled by pellet injection. The effects of the ambipolar radial electric field and the electron density peaking on the turbulent ion heat transport are separately evaluated using large-scale gyrokinetic simulations. The essential role of the stellarator magnetic geometry is demonstrated, by comparison with a tokamak.

Turbulence Mechanisms of Enhanced Performance Stellarator Plasmas