Field-reversed experiments (FRX) on compact toroids

Journal Article · Sun Nov 01 04:00:00 EST 1981 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.863303· OSTI ID:6062472

Armstrong, W T; Linford, R K; Lipson, J; Platts, D A; Sherwood, E G

Equilibrium, stability, and confinement properties of compact toroids produced in field-reversed theta-pinch experiments (FRX) are reported. Two experimental facilities, FRX-A and FRX-B, have been used to study highly elongated compact toroid plasmas confined in a purely poloidal field geometry. Spatial scans and fill pressure scaling of the equilibrium plasma parameters are presented. Plasma conditions range from T/sub e/approx.150 eV, T/sub i/approx.800 eV, n/sub m/approx.1 x 10/sup 15/ cm/sup -3/ to T/sub e/approx.100 eV, T/sub i/approx.150 eV, n/sub m/approx.4 x 10/sup 15/ cm/sup -3/. Typical confined plasma dimensions are: major radius Rapprox.4 cm, minor radius aapprox.2 cm, and total length 35--50 cm. The plasma configuration remains in a stable equilibrium for up to 50 ..mu..sec followed by the destructive n = 2 rotational instability. The stable period prior to the onset of the rotational mode is up to one hundred times greater than characteristic Alfven transit times of the plasma. This stable period increases and the mode growth rate decreases with increased a/rho/sub i/ (where rho/sub i/ is the ion gyroradius). Agreement of experimental and theoretical mode frequencies for the instability is observed. Preferential particle loss has been proposed as a likely cause of rotation. The particle inventory at the onset of the instability is consistent with this hypothesis. The particle loss rate is also consistent with the predicted anomalous transport near the separatrix. Contributions to rotational instability from diffusion, end-shorting, equipartition, and compression are also discussed.

• Research Organization: Los Alamos Scientific Laboratory, University of California, Los Alamos, New Mexico 87545
• OSTI ID: 6062472
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 24:11; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101 -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
700107* -- Fusion Energy-- Plasma Research-- Instabilities
CLOSED PLASMA DEVICES
CONFINEMENT
ELECTRON TEMPERATURE
EQUILIBRIUM
INSTABILITY GROWTH RATES
ION TEMPERATURE
MOTION
PINCH DEVICES
PINCH EFFECT
PLASMA CONFINEMENT
REVERSE-FIELD PINCH
ROTATION
STABILITY
THERMONUCLEAR DEVICES
TOROIDAL PINCH DEVICES
TOROIDAL THETA PINCH DEVICES