Scale-selective turbulence reduction in H-mode plasmas in the TJ-II stellarator

Journal Article · Sat Oct 15 04:00:00 EDT 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3646315· OSTI ID:22046945

Happel, T; Conway, G D; Stroth, U ^[1]; Estrada, T; Blanco, E; Hidalgo, C

---

1. Max-Planck-Institut fuer Plasmaphysik, Association Euratom-IPP, 85748 Garching (Germany)

Wavenumber spectra of density turbulence in L- and H-mode plasmas have been measured in the TJ-II stellarator by means of Doppler reflectometry. A pronounced suppression of the density fluctuation level is observed in H-mode close to the radial position of maximum radial electric field (E{sub r}) shear. Furthermore, intermediate scale density turbulence is reduced preferentially. This effect can be interpreted within the framework of vortex stretching feeding energy through Reynolds stress into zonal flows, while shear decorrelation of turbulent structures might not play a central role in TJ-II. Moreover, it is shown that in both L- and H-mode, the phase velocity of density fluctuations does not depend on the structure scale.

• OSTI ID: 22046945
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 10 Vol. 18; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ELECTRIC FIELDS
FLUCTUATIONS
H-MODE PLASMA CONFINEMENT
L-MODE PLASMA CONFINEMENT
PHASE VELOCITY
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
PLASMA INSTABILITY
REYNOLDS NUMBER
SHEAR
STRESSES
TJ-II HELIAC
TURBULENCE
VORTICES