Abstract Details
Abstracts
Author: Eamon J Hartigan-O'Connor
Requested Type: Poster
Submitted: 2025-03-14 21:54:34
Co-authors: V.N. Duarte, T. Barberis
Contact Info:
Princeton University
307 Court St, B244
Princeton, NJ 08540
United States
Abstract Text:
In a burning plasma, the destabilization of Alfvén eigenmodes (AEs) by fast ions may lead to increased energetic particle (EP) transport and decreased confinement. Previous studies have also found that AEs can nonlinearly beat against themselves to drive zonal flows (ZFs), which themselves play a central role in regulating drift-wave (DW) turbulence. It is less understood how beat-driven ZFs affect the AEs directly, which is essential in order to create a reduced model for this process. However, ZF shearing of DW turbulence may reduce the effective scattering felt by the EPs, thereby reducing the AE drive. We investigate the effects of a time-dependent scattering on a reduced model for beat-driven ZF, using gyrokinetic estimates for modifications of turbulent effective scattering by a background ZF. We also investigate the analytical implications of a time-dependent collisionality on the Berk-Breizman cubic equation, showing that the equation may be cast in a time-local form only when the time derivative of the collisionality, divided by the square of the collisionality, is sufficiently small. We show that both strong-shear and weak-shear estimates for ZF-modified collisionality satisfy this requirement.
Characterization: 1.0
Comments:
If possible, please place my poster next to those of Vinicius Duarte and Emma Devin.