Reducing turbulent transport in tokamaks by combining intrinsic rotation and the low momentum diffusivity regime

Based on the analysis of a large number of high-fidelity nonlinear gyrokinetic simulations, we propose a novel strategy to improve confinement in spherical tokamak plasmas by combining up-down asymmetric flux surface shaping with the Low Momentum Diffusivity (LMD) regime. We show that the intrinsic...

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Detalles Bibliográficos
Autores: Sun, Haomin, Ball, Justin, Brunner, Stephan, Field, Anthony, Cruz Zabala, Diego José, Viezzer, Eleonora, García Muñoz, Manuel
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Institución:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/178926
Acceso en línea:https://hdl.handle.net/11441/178926
https://doi.org/10.1088/1741-4326/ade1ed
Access Level:acceso abierto
Palabra clave:Plasma transport
Plasma turbulence
Prandtl number
Flow shear
Turbulence stabilization
Flux surface geometry
Momentum diffusivity
Descripción
Sumario:Based on the analysis of a large number of high-fidelity nonlinear gyrokinetic simulations, we propose a novel strategy to improve confinement in spherical tokamak plasmas by combining up-down asymmetric flux surface shaping with the Low Momentum Diffusivity (LMD) regime. We show that the intrinsic momentum flux driven by up-down asymmetry creates strong flow shear in the LMD regime that can significantly reduce energy transport, increasing the critical gradient by up to 25%. In contrast to traditional methods for generating flow shear, such as neutral beam injection, this approach requires no external momentum source and is expected to scale well to large fusion devices. The experimental applicability of this strategy in spherical tokamaks is addressed via simulations by considering actual equilibria from Mega Ampere Spherical Tokamak and a preliminary equilibrium from SMART.