Turbulence Suppression by Energetic Particle Effects in Modern Optimized Stellarators.

Area of Science:

• Plasma Physics
• Fusion Energy Research
• Computational Astrophysics

Background:

• Turbulent transport is a major obstacle to achieving efficient plasma confinement in optimized stellarators.
• Existing stellarator designs struggle with plasma instabilities that degrade performance.

Purpose of the Study:

• To introduce and validate a novel method for suppressing plasma turbulence in stellarators.
• To investigate the role of resonant wave-particle interactions involving suprathermal particles.

Main Methods:

• Employed large-scale gyrokinetic simulations to model plasma behavior.
• Focused on the interaction between suprathermal particles (e.g., from ion-cyclotron-resonance-frequency heating) and turbulence-driving microinstabilities (e.g., ion-temperature-gradient modes).

Main Results:

• Demonstrated significant turbulence reduction, up to 65%, through the proposed resonant wave-particle interaction mechanism.
• Highlighted the crucial influence of magnetic geometry in stellarator configurations compared to tokamaks.
• Initiated the optimization of fast particle effects for enhanced stellarator performance.

Conclusions:

• The resonant wave-particle interaction is an effective strategy for suppressing turbulence in stellarators.
• This approach offers a pathway to new stellarator scenarios with improved plasma confinement.
• Results are crucial for the development of future fusion energy devices, particularly those requiring burning plasmas.