Experimental characterization of drift-interchange instabilities in a simple toroidal plasma

Journal Article · Sun Oct 15 00:00:00 EDT 2006 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2356483· OSTI ID:20860283

Poli, F M; Brunner, S; Diallo, A; Fasoli, A; Furno, I; Labit, B; Mueller, S H; Plyushchev, G; Podesta, M ^[1]

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1. CRPP-EPFL, Association EURATOM-Confederation Suisse, Lausanne (Switzerland)

Low frequency electrostatic instabilities are investigated on TORPEX [Fasoli, Labit, McGrath, Mueller, Podesta, and Poli, Bull. Am. Phys. Soc. 48, 119 (2003)], a toroidal device for basic plasma physics experiments with a toroidal magnetic field 100 mT and a small vertical magnetic field ({<=}4 mT). A two-dimensional (2D) profile of the frequency and amplitude of density and potential fluctuations is reconstructed using electrostatic probes with high space and time resolution. The measured phase velocity, corrected for the Doppler shift induced by the ExB drift, is consistent with the electron diamagnetic drift velocity. The local dispersion relation, measured along and across the magnetic field, is in agreement with the predictions of a linear kinetic slab model for drift waves. Unstable modes are generated in regions of unfavorable curvature, where the pressure gradient is colinear with the magnetic field gradient. It is demonstrated that the curvature of the magnetic field lines is essential for driving the observed instabilities, which are therefore identified as drift-interchange modes.

• OSTI ID: 20860283
• Journal Information: Physics of Plasmas, Vol. 13, Issue 10; Other Information: DOI: 10.1063/1.2356483; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DOPPLER EFFECT
DRIFT INSTABILITY
ELECTROMAGNETIC FIELDS
ELECTRONS
ELECTROSTATIC PROBES
FLUCTUATIONS
FLUTE INSTABILITY
MAGNETIC FIELDS
PHASE VELOCITY
PLASMA
PLASMA CONFINEMENT
PLASMA DENSITY
PLASMA DIAMAGNETISM
PLASMA DRIFT
PLASMA POTENTIAL
PLASMA PRESSURE
PLASMA WAVES
PRESSURE GRADIENTS
RADIATION TRANSPORT
TIME RESOLUTION
TOKAMAK DEVICES
TWO-DIMENSIONAL CALCULATIONS