Turbulence Suppression by Energetic Particle Effects in Modern Optimized Stellarators

Turbulent transport is known to limit the plasma confinement of present-day optimized stellarators. To address this issue, a novel method to strongly suppress turbulence in such devices is proposed, namely the resonant wave-particle interaction of suprathermal particles-e.g., from ion-cyclotron-reso...

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Bibliographic Details
Published in:Physical review letters 2020-09, Vol.125 (10), p.1-105002, Article 105002
Main Authors: Di Siena, A., Bañón Navarro, A., Jenko, F.
Format: Article
Language:English
Subjects:
Cyclotron resonance
Energetic particles
Optimization
Particle interactions
Plasmas
Stellarators
Tokamak devices
Turbulence
Wave-particle interactions
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Summary:Turbulent transport is known to limit the plasma confinement of present-day optimized stellarators. To address this issue, a novel method to strongly suppress turbulence in such devices is proposed, namely the resonant wave-particle interaction of suprathermal particles-e.g., from ion-cyclotron-resonance-frequency heating-with turbulence-driving microinstabilities like ion-temperature-gradient modes. The effectiveness of this mechanism is demonstrated via large-scale gyrokinetic simulations, revealing an overall turbulence reduction by up to 65% in the case under consideration. Comparisons with a tokamak configuration highlight the critical role played by the magnetic geometry and the first steps into the optimization of fast particle effects in stellarator devices are discussed. These results hold the promise of new and still unexplored stellarator scenarios with reduced turbulent transport, essential for achieving burning plasmas in future devices.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.125.105002