Electrostatic potential variations along flux surfaces in stellarators

Abstract

First observations of electrostatic potential variations within the flux surfaces of a toroidal magnetic confinement device are presented. Measurements are taken in the TJ-II stellarator with two distant Langmuir probe arrays. The edge floating potentials display differences of several tens of Volts in electron-root wave-heated plasmas. The differences are reduced for higher densities and lower electron temperatures after the ion-root electric field forms at the plasma edge. Neoclassical Monte Carlo simulations estimate the correct order of magnitude for the overall variation in potential and predict the trend observed with the radial electric field. However, for the specific location of the probes, the simulations give differences smaller than those observed experimentally.

References in corpus (2)

• Vanishing neoclassical viscosity and physics of the shear layer in stellarators
• Dynamic transport regulation by zonal flow-like structures in the TJ-II stellarator

Cited by in corpus (9)

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• KNOSOS: a fast orbit-averaging neoclassical code for stellarator geometry
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• Large tangential electric fields in plasmas close to temperature screening
• Robust stellarator optimization via flat mirror magnetic fields
• On-surface potential and radial electric field variations in electron root stellarator plasmas
• Parallel impurity dynamics in the TJ-II stellarator
• Optimization of flux-surface density variation in stellarator plasmas with respect to the transport of collisional impurities
• Effects of collisions on impurity transport driven by electrostatic modes