19th Technical Meeting on Energetic Particles in Magnetic Confinement Systems

Session

Synergy EP and turbulence

28 Sept 2026, 11:00

Beaulieu Congress and Exhibition Center (Lausanne, Switzerland)

3. Theory of Zonal Fields Beat Driven by Alfvén Eigenmodes in Tokamak Plasmas

Prof. LIU CHEN (UNIVERSITY OF CALIFORNIA, IRVINE)

28/09/2026, 11:00

Invited

We have further extended previously derived expressions for zonal electromagnetic fields (ZFs) beat driven by reversed shear Alfvén eigenmode (RSAE) [L. Chen et al., Nucl. Fusion 65 (2025) 016018] to the case of toroidal Alfvén eigenmode (TAE). It is found that the expression of zonal current (i.e., the zonal component of the parallel vector potential) remains robust. The expression of the...

53. On the Beat Driven Nonlinear Excitation of Zero Frequency Zonal Fields by Alfvén Eigenmodes

Riccardo Stucchi

28/09/2026, 11:35

Poster session I

Poster

Simulations and experiments have shown that zonal flows can play a crucial role in the regulation of turbulence. In the context of energetic particles physics for magnetic confinement devices, it is then interesting to study how the interplay of energetic particles and Alfvén eigenmodes can affect the dynamics of zonal flows, and more in general zonal structures, and potentially impact the...

64. First Experimental Studies of Energetic Particle-Turbulence Dynamics in Spherical Tokamak Plasmas

Phillip Bonofiglo (PPPL - Princeton Plasma Physics Laboratory (US))

28/09/2026, 12:00

Synergy EP/turbulence I

Oral

This report presents experimental and modeling studies on the interaction between energetic particles, Alfvén eigenmodes (AEs), and thermal plasma turbulence in neutral-beam-heated MAST-U spherical tokamak plasmas. These studies address the nonlinear coupling between fast-ion-driven MHD activity and microturbulence, with emphasis on the impact of energetic particles on turbulence regulation...

5. Fine Structure of Sheared Flow Driven by Fishbone Instability in Tokamak Plasma

Yuehao Ma (University of Science and Technology of China)

28/09/2026, 12:25

Synergy EP/turbulence I

Oral

In tokamaks, it is well established that sheared flows mitigate turbulence that drives heat and particle transport, thereby providing a direct pathway to improved confinement. In particular, achieving the ITER steady-state and long-pulse high-performance operation relies on the internal transport barrier (ITB), a narrow region of steep pressure gradients that improves core plasma...

43. Energetic-particle-driven Alfvénic bursts and zonal structures in JET: DBS measurements and gyrokinetic simulations

Dr Juan Ruiz ruiz (University of York (EU))

01/10/2026, 09:00

Fast electrons and runaways

Invited

We report Doppler backscattering (DBS) measurements and gyrokinetic simulations of alternating Alfvénic bursts in a JET plasma previously analysed by Ruiz Ruiz et al. [Phys. Rev. Lett. 134, 095103 (2025)]. The DBS measurements show that fluctuation power in the ITG-turbulence frequency range is anticorrelated with the fluctuation power of modes in the gaps of the Alfvénic spectrum, with the...

41. Experimental observation of microturbulence suppression induced by Alfvén Eigenmodes in DIII-D tokamak

Xiaodi Du (GAT - Fusion Energy Research General Atomics (US))

01/10/2026, 09:35

Fast electrons and runaways

Invited

The suppression of ion temperature gradient (ITG) turbulence by the nonlinear evolution of toroidicity-induced Alfvén eigenmodes (TAEs) is demonstrated in the DIII-D tokamak [1]. Systematic measurements of plasma parameters reveal that this phenomenon is characterized by: (1) a reduction in the poloidal correlation length of ITG from 5 cm to 2 cm and a 30% decrease in the radial correlation...

49. On How Zonal Fields Suppress Reversed Shear Alfvén Eigenmode in Tokamak Plasmas: Simulation and Theory

Ruirui Ma

01/10/2026, 10:10

Fast electrons and runaways

Oral

Achieving good confinement in tokamak advanced scenarios requires understanding and controlling Alfvénic instabilities driven by energetic particles (EPs). Reversed-shear Alfvén eigenmodes (RSAEs) [1, 2] are commonly observed in plasmas with nonmonotonic safety-factor profiles and can cause substantial EP transport and losses, making their nonlinear saturation mechanisms critical for...

28. Properties of Alfven eigenmodes during strong turbulence suppression*

William Heidbrink

01/10/2026, 10:35

Fast electrons and runaways

Oral

Alfvén eigenmodes (AE) create a regime in the DIII-D tokamak where zonal flows and currents strongly suppress ion-temperature-gradient (ITG) turbulence. This oral focuses on the differences between AEs in the strongly suppressed ITG regime and “normal" AEs in unsuppressed plasmas. Strongly suppressed cases are compared to closely matched reference shots at several stages: (1) before the...