Space-time statistics of the turbulence in the PRETEXT and TEXT tokamak edge plasmas

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5370469

Levinson, S J

A study of the statistical space-time properties of the turbulence observed in the edge regions of the PRETEXT and the TEXT tokamaks are reported. Computer estimates of the particle-transport spectrum T(omega), and of the local wavenumber-frequency spectra S(K,omega) for poloidal (k/sub y/) and toroidal (k/sub z/) wavenumbers was determined. A conventional fast-Fourier-transform technique is used initially for the analyses of the potential and density fluctuations obtained from spatially fixed Langmuir-probe pairs. Measurements of the fluctuation-induced particle transport revealed that the particle flux is outward for both PRETEXT and TEXT, and it results primarily from the low-frequency, long-wavelength components of the turbulence. The S(K/sub y/, omega) spectra are dominated by low frequencies (<200 kHz) and small wavenumbers (<4 cm/sup -1/) and appear broadened about an approximately linear statistical dispersion relation, anti k(omega). The broadening is characterized by a spectral width sigma/sub k/(omega) (rms deviation about anti k(omega)). In PRETEXT, sigma/sub k/(omega) is of the order of anti k(omega), and the turbulence appears to propagate poloidally with an apparent mean phase velocity of 1-2 x 10/sup 5/ cm/s in the ion diamagnetic drift direction. In TEXT, a reversal in the phase velocity of the turbulence in the edge plasma was observed.

• Research Organization: Texas Univ., Austin (USA)
• OSTI ID: 5370469
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102 -- Fusion Energy-- Plasma Research-- Diagnostics
700103* -- Fusion Energy-- Plasma Research-- Kinetics
CLOSED PLASMA DEVICES
CLUSTER EMISSION MODEL
ELECTRIC PROBES
ION DRIFT
LANGMUIR PROBE
MATHEMATICAL MODELS
MULTIPERIPHERAL MODEL
PARTICLE MODELS
PERIPHERAL MODELS
PLASMA DENSITY
PLASMA DIAGNOSTICS
POTENTIALS
PROBES
SPACE-TIME MODEL
TEXT DEVICES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TURBULENCE