Incompressibility of Impurity Flows in Low Density TJ-II Plasmas and Comparison with Neoclassical Theory

Abstract

Poloidal and toroidal velocities of fully-ionised carbon are measured by means of charge exchange recombination spectroscopy (CXRS) in the TJ-II stellarator. We present a detailed treatment of the 3D geometry and show that flow measurements, performed at different locations of the same flux surface, are compatible with flow incompressibility for the low density plasmas under study (line averaged electron densities ${\bar{n}}_e\le 10^{19}$ m${}^{-3}$). Furthermore, comparison with neoclassical calculations shows quantitative agreement with the measured radial electric field and ion bootstrap parallel flow in the absence of an external momentum input.

arXiv comment17 pages, 10 figures

References in corpus (3)

• Vanishing neoclassical viscosity and physics of the shear layer in stellarators
• Calculation of the bootstrap current profile for the TJ-II stellarator
• Study of the neoclassical radial electric field of the TJ-II flexible heliac

Cited by in corpus (5)

• Electrostatic potential variations along flux surfaces in stellarators
• Damping of radial electric field fluctuations in the TJ-II stellarator
• Compressible impurity flow in the TJ-II stellarator
• Parallel impurity dynamics in the TJ-II stellarator
• On the interplay between turbulent forces and neoclassical particle losses in Zonal Flow dynamics