Abstract Details
Abstracts
Author: Nikolai Gorelenkov
Requested Type: Poster
Submitted: 2024-04-14 20:56:55
Co-authors: V.N. DUARTE, M.V. GORELENKOVA
Contact Info:
PPPL, Princeton University
POBox 451
Princeton, New Jersey 08543
USA
Abstract Text:
We tackle a serious challenge concerning future burning plasmas: whether high-energy fusion products, alpha particles, and/or auxiliary heating beam ions will remain confined long enough to compensate for thermal plasma energy losses. This challenge can be influenced by one of the most detrimental collective phenomena: the instability of low-frequency Alfvén eigenmodes (AEs), including toroidicity-induced AEs and reversed shear Alfvén eigenmodes. Utilizing the recently built resonance broadened quasi-linear code RBQ (N.N.Gorelenkov and V.N.Duarte, Phys.Lett A 2021) which is based on a recently revisited quasi-linear theory (V.~N.~Duarte et al., PRL, 2023) we consider the ITER steady-state scenario to evaluate the potential effect of unstable AEs on various fast ion's relaxation. We discover that AE instabilities can impact both neutral beam ions and alphas, although resulting fast ion transport is expected to be minimal under the assumption of classical particle slowing down. Conversely, the QL theory suggests that AE amplitudes could be amplified by background microturbulence, although this aspect falls outside the scope of our current study due to the substantial numerical efforts required for evaluation. Our investigation delves into EP relaxation dynamics employing various tools: a comprehensive linear stability study of the sub-cyclotron Alfvénic spectrum computed by ideal MHD simulations using NOVA, drift kinetic calculations utilizing NOVA-C for wave-particle interaction and AE growth/damping rates, and predictive quasi-linear modeling coupled with the global particle code NUBEAM to evaluate EP relaxation on the equilibrium time scale. One potential problem for ITER plasma operations is the effect of the Alfvénic modes on the current drive which could work against the self-sustained steady-state plasma scenario.
Comments:
Please put this abstract to other then my other abstract.
Put it into this section:
Analytic and computational methods for modeling plasmas