Properties of convective cells generated in magnetized toroidal plasmas

Journal Article · Wed Aug 15 04:00:00 EDT 2012 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4740056· OSTI ID:22086014

Theiler, C; Loizu, J; Furno, I; Fasoli, A; Ricci, P ^[1]

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1. Centre de Recherches en Physique des Plasmas-Ecole Polytechnique Federale de Lausanne (EPFL), Association EURATOM-Confederation Suisse, CH-1015 Lausanne (Switzerland)

Convective cells for turbulence control, generated by means of biased electrodes, are investigated in the simple magnetized toroidal plasmas of TORPEX. A two-dimensional array of 24 electrodes is installed on a metal limiter to test different biasing schemes. This allows influencing significantly both radial and vertical blob velocities. It is shown that these changes agree quantitatively with the flows deduced from the time averaged potential perturbations induced by the biasing. Detailed measurements along and across the magnetic field provide a rather clear picture of the effect of biasing on time averaged profiles. The biased electrodes produce perturbations of the plasma potential and density profiles that are fairly uniform along the magnetic field. Background flows influence the location where potential variations are induced. The magnitude of the achievable potential variations in the plasma is strongly limited by cross-field currents and saturates at large bias voltages once the electrodes draw electron saturation current. A quantitative discussion on the origin of cross-field currents is presented, considering contributions related with diamagnetic drifts, ion inertia, collisions with neutrals, and viscosity.

• OSTI ID: 22086014
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 8 Vol. 19; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM CURRENTS
DENSITY
DISTURBANCES
ELECTRODES
ELECTRONS
ION DRIFT
MAGNETIC FIELDS
PLASMA
PLASMA DENSITY
PLASMA POTENTIAL
TOKAMAK DEVICES
TURBULENCE
TWO-DIMENSIONAL CALCULATIONS