Impact of Energetic-Particle-Driven Geodesic Acoustic Modes on Turbulence

D. Zarzoso (1) , Y. Sarazin (1) , X. Garbet (1) , R. Dumont (1) , A. Strugarek (1, 2) , J. Abiteboul (1) , T. Cartier-Michaud (1) , Guilhem Dif-Pradalier (1) , Ph. Ghendrih (1) , V. Grandgirard (1) , G. Latu (1) , C. Passeron (1) , O. Thomine (1)

1 IRFM - Institut de Recherche sur la Fusion par confinement Magnétique
2 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation

The impact on turbulent transport of geodesic acoustic modes excited by energetic particles is evidenced for the first time in flux-driven 5D gyrokinetic simulations using the Gysela code. Energetic geodesic acoustic modes (EGAMs) are excited in a regime with a transport barrier in the outer radial region. The interaction between EGAMs and turbulence is such that turbulent transport can be enhanced in the presence of EGAMs, with the subsequent destruction of the transport barrier. This scenario could be particularly critical in those plasmas, such as burning plasmas, exhibiting a rich population of suprathermal particles capable of exciting energetic modes.

Keywords: 52.35.Ra; 52.30.Gz; 52.35.Qz; 52.65.Tt; Plasma turbulence; Gyrokinetics; Microinstabilities; Gyrofluid and gyrokinetic simulations

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]

D. Zarzoso, Y. Sarazin, X. Garbet, R. Dumont, A. Strugarek, et al.. Impact of Energetic-Particle-Driven Geodesic Acoustic Modes on Turbulence. Physical Review Letters, 2013, 110, ⟨10.1103/PhysRevLett.110.125002⟩. ⟨insu-03621042⟩