Work

Reduced model describing resonance overlap threshold for fast ion transport by toroidal Alfvén eigenmodes

Year: 2025

Type: article

Abstract: This work introduces a reduced model to predict the ‘resonance overlap threshold’ governing transport of fast ions (FIs) by toroidal Alfvén eigenmodes (TAEs) in tokamak plasmas. TAE-FI resonance occurs within distinct ‘resonance regions’ of particle phase space, which grow wider when the TAE mode amplitude increases. If these resonance regions are separate then FI transport is limited and localised; if multiple resonance regions overlap then large-scale stochastic transport of FIs can occur, jeopardising confinement. Predicting the resonance overlap threshold between these two scenarios is an important problem in the field of FI transport modelling. Current workflows rely on computationally expensive orbit-following codes; the new reduced resonance overlap model provides a much simpler and faster alternative, for ease of implementation in integrated models. In this paper, we apply this approach to passing particles and find good agreement with more detailed numerical modelling, including HALO code simulations. Models based on this approach could provide a useful step in increasing efficiency of predictive modelling for next-generation fusion reactors.

Source: Nuclear Fusion

DOI: 10.1088/1741-4326/ae2938

Authors: R. Blyth, M. Fitzgerald, B.N. Breizman

Institutions: Durham University, United Kingdom Atomic Energy Authority, The University of Texas at Austin

Language: English

Topic: Magnetic confinement fusion research

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,595

Funders: U.S. Department of Energy, Uppsala Universitet, Engineering and Physical Sciences Research Council