Zonal flow suppression of turbulent transport in the optimized stellarators W7-X and QSTK

Fuente: arXiv
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Main Authors: Tiwari, Abhishek, Das, Joydeep, Alageshan, Jaya Kumar, Roberg-Clark, Gareth, Plunk, Gabriel, Xanthopoulos, Pavlos, Sharma, Sarveshwar, Lin, Zhihong, Kuley, Animesh
Format: Preprint
Published: 2025
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author Tiwari, Abhishek
Das, Joydeep
Alageshan, Jaya Kumar
Roberg-Clark, Gareth
Plunk, Gabriel
Xanthopoulos, Pavlos
Sharma, Sarveshwar
Lin, Zhihong
Kuley, Animesh
author_facet Tiwari, Abhishek
Das, Joydeep
Alageshan, Jaya Kumar
Roberg-Clark, Gareth
Plunk, Gabriel
Xanthopoulos, Pavlos
Sharma, Sarveshwar
Lin, Zhihong
Kuley, Animesh
contents We present a comparative study of transport in two optimized stellarator configurations: Wendelstein 7-X (W7-X) and a recent design called Quasi-Symmetric Turbulence Konzept (QSTK). Using global Gyrokinetic Toroidal Code (GTC), we explore the role of zonal flows (ZFs) in suppressing electrostatic Ion Temperature Gradient (ITG) driven turbulence in both configurations. The simulations reveal that ZFs significantly reduce ion heat transport in both W7-X and QSTK, with a lower value of heat flux on the latter configuration, as suggested by the apparently higher linear threshold (''critical'') gradients for ITG modes. The study also highlights that both stellarators exhibit similar mode structures. The results support the notion that linear stability measures, in combination with nonlinear stabilization by zonal flows, can play an important role in the suppression of nonlinear heat fluxes.
format Preprint
id arxiv_https___arxiv_org_abs_2501_12722
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Zonal flow suppression of turbulent transport in the optimized stellarators W7-X and QSTK
Tiwari, Abhishek
Das, Joydeep
Alageshan, Jaya Kumar
Roberg-Clark, Gareth
Plunk, Gabriel
Xanthopoulos, Pavlos
Sharma, Sarveshwar
Lin, Zhihong
Kuley, Animesh
Plasma Physics
We present a comparative study of transport in two optimized stellarator configurations: Wendelstein 7-X (W7-X) and a recent design called Quasi-Symmetric Turbulence Konzept (QSTK). Using global Gyrokinetic Toroidal Code (GTC), we explore the role of zonal flows (ZFs) in suppressing electrostatic Ion Temperature Gradient (ITG) driven turbulence in both configurations. The simulations reveal that ZFs significantly reduce ion heat transport in both W7-X and QSTK, with a lower value of heat flux on the latter configuration, as suggested by the apparently higher linear threshold (''critical'') gradients for ITG modes. The study also highlights that both stellarators exhibit similar mode structures. The results support the notion that linear stability measures, in combination with nonlinear stabilization by zonal flows, can play an important role in the suppression of nonlinear heat fluxes.
title Zonal flow suppression of turbulent transport in the optimized stellarators W7-X and QSTK
topic Plasma Physics
url https://arxiv.org/abs/2501.12722