Turbulence-Generated Stepped Safety Factor Profiles in Tokamaks with Low Magnetic Shear
Abstract
Nonlinear local and global gyrokinetic simulations of tokamak plasmas demonstrate that turbulence-generated currents flatten the safety factor profile near low-order rational surfaces when magnetic shear is low, even when the plasma is small. A large set of flux tube simulations with different safety factor profiles (e.g. linear and non-linear safety factor profiles) and global simulations with reversed magnetic shear profiles show that such stepped safety factor profiles dramatically reduce the heat transport and are a robust phenomenon. This mechanism may play a key role in the triggering of internal transport barriers (ITBs) and more generally reveal novel strategies for improving confinement in devices with low magnetic shear.
Keywords
Cite
@article{arxiv.2502.04459,
title = {Turbulence-Generated Stepped Safety Factor Profiles in Tokamaks with Low Magnetic Shear},
author = {Arnas Volčokas and Justin Ball and Giovanni Di Giannatale and Stephan Brunner},
journal= {arXiv preprint arXiv:2502.04459},
year = {2025}
}
Comments
4 pages, 4 figures