Edge fluctuations in the MST (Madison Symmetric Torus) reversed field pinch

Conference · Mon Oct 01 00:00:00 EDT 1990

OSTI ID:6300007

Almagri, A; Assadi, S; Beckstead, J; Chartas, G; Crocker, N; Den Hartog, D; Dexter, R; Hokin, S; Holly, D; Nilles, E; Prager, S; Rempel, T; Sarff, J; Scime, E; Shen, W; Spragins, C; Sprott, J; Starr, G; Stoneking, M; Watts, C

Edge magnetic and electrostatic fluctuations are measured in the Madison Symmetric Torus (MST) reversed field pinch. At low frequency (<25 kHz), the mode number spectra of magnetic fluctuations agree very well with theoretical prediction for nonlinearly saturated tearing fluctuations resonant in the core. At high frequency (50 kHz to 100 kHz) the magnetic spectra broaden and the modes become resonant in the reversal region. Nonlinear phenomena are under experimental investigation. The low frequency fluctuations phase-lock together to produce a rotating localized disturbance. Bi-spectral analysis in frequency also reveals nonlinear three-wave mode-coupling at low frequency. Electrostatic fluctuations are substantial and do not appear to obey a Boltzmann relation (i.e. e{tilde {phi}}/kT{sub e} > {tilde p}{sub e}/p{sub e} where {tilde {phi}} and {tilde p}{sub e} are the fluctuating potential and pressure, respectively). From measurements of the fluctuating density, temperature, and potential we infer that the electrostatic fluctuation induced transport of particles and energy can be substantial. 13 refs., 11 figs.

• Research Organization: Wisconsin Univ., Madison, WI (USA). Plasma Physics Research
• Sponsoring Organization: DOE/ER
• DOE Contract Number: FG02-85ER53198
• OSTI ID: 6300007
• Report Number(s): DOE/ER/53198-164; CONF-9010209-8; ON: DE91004923; TRN: 91-001245
• Resource Relation: Conference: Workshop on physics of alternative magnetic confinement schemes, Varenna (Italy), 14-15 Oct 1990
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
REVERSE-FIELD PINCH
FLUCTUATIONS
BOUNDARY LAYERS
FREQUENCY DEPENDENCE
MAGNETIC FIELDS
MHD EQUILIBRIUM
PLASMA WAVES
EQUILIBRIUM
LAYERS
PINCH EFFECT
VARIATIONS
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