  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 supra-thermal particles - e.g., from
ion-cyclotron-resonance-frequency (ICRF) heating - with turbulence-driving
microinstabilities like ion-temperature-gradient (ITG) modes. The effectiveness
of this mechanism is demonstrated via analytic theory and large-scale
gyrokinetic simulations, revealing an overall turbulence reduction by up to
$80\%$. These results hold the promise of new and still unexplored stellarator
scenarios with enhanced confinement and improved performance, essential for
achieving burning plasmas in future devices.
