Reducing turbulent transport in tokamaks by combining intrinsic rotation and the low momentum diffusivity regime
Abstract 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.
Authors
- B. Patel (ORCID: https://orcid.org/0000-0003-0121-1187)
- C.M. Roach (ORCID: https://orcid.org/0000-0001-5856-0287)
- M. García-Muñoz (ORCID: https://orcid.org/0000-0002-3241-502X)
- Daniel Kennedy (ORCID: https://orcid.org/0000-0001-7666-782X)
- S. Brunner
- A. R. Field (ORCID: https://orcid.org/0000-0003-0671-9668)
- E. Viezzer (ORCID: https://orcid.org/0000-0001-6419-6848)
- Justin Ball (ORCID: https://orcid.org/0000-0002-4462-6350)
- Haomin Sun (ORCID: https://orcid.org/0000-0001-7403-6450)
- D. J. Cruz-Zabala (ORCID: https://orcid.org/0000-0001-5925-5153)
- Fernando Puentes Del Pozo (ORCID: https://orcid.org/0000-0001-8836-341X)
Institutions
- United Kingdom Atomic Energy Authority (GB)
- École Polytechnique Fédérale de Lausanne (CH)
- Universidad de Sevilla (ES)
Publication Details
- Journal
- Nuclear Fusion
- Published
- 2025-06-06
- DOI
- https://doi.org/10.1088/1741-4326/ade1ed
- Citations
- 1
- Primary Topic
- Magnetic confinement fusion research
- Type
- article
- Field-Weighted Citation Impact
- 1.87
Funders
- Centro Svizzero di Calcolo Scientifico
- nccr – on the move
- Euratom Research and Training Programme