New high-confinement regime with fast ions in the core of fusion plasmas

Abstract

The key result of the present work is the theoretical prediction and observation of the formation of a new type of transport barrier in fusion plasmas, called F-ATB (fast ion-induced anomalous transport barrier). As demonstrated through state-of-the-art global electrostatic and electromagnetic simulations, the F-ATB is characterized by a full suppression of the turbulent transport - caused by strongly sheared, axisymmetric $E\times B$ flows - and an increase of the neoclassical counterpart, albeit keeping the overall fluxes at significantly reduced levels. The trigger mechanism is shown to be a mainly electrostatic resonant interaction between supra-thermal particles, generated via ion-cyclotron-resonance heating, and plasma micro-turbulence. These findings are obtained by realistic simulations of the ASDEX Upgrade discharge $\#36637$ - properly designed to maximized the beneficial role of the wave-particle resonance interaction - which exhibits the expected properties of improved confinement produced by energetic particles.

Version 2

References in corpus (1)

• Turbulence suppression by energetic particle effects in modern optimized stellarators

Cited by in corpus (10)

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• Momentum Conservation in Current Drive and Alpha-Channeling-Mediated Rotation Drive
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• A novel approach to radially global gyrokinetic simulation using the flux-tube code $\text{stella}$
• Turbulence suppression by energetic particles: A sensitivity-driven dimension-adaptive sparse grid framework for discharge optimization
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• Fast ion effects on the threshold conditions of ion temperature gradient mode and electron temperature gradient mode