Experimental investigation of compact toroid formation, dynamics, and plasma loss in a field reversed theta pinch

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

OSTI ID:6842824

Mead, Jr, F B

Results of an experimental investigation of compact toroid formation, dynamics, and plasma loss in a 50-cm-long field reversed theta pinch are presented. A combination of radio frequency incipient ionization coupled with fast ringing theta discharges was used to trap a uniform 0.92 kG magnetic bias field in a deuterium gas over a 20 to 200 mtorr fill pressure range in a 9-cm diameter discharge tube. A reversed 4.54 kJ crowbarred discharge with a rise time of 3.4 ..mu..s was used to form compact toroids exhibiting lifetimes up to 60 ..mu..s. A diamagnetic loop, magnetic loop, magnetic probes, pressure probes, spectroscopy, photodiodes, and photography were used as diagnostics to investigate preionization, bias field generation, and trapping, stable lifetime characteristics, and eventual compact toroid destruction. Separatrix radius electron temperature, and electron density as a function of time and pressure are calculated from experimental data. Symmetry and rotational stability are illustrated over the lifetime of the compact toroids. Results indicate that like the Russian experiments but unlike the results at Los Alamos, compact toroids formed in the Penn State machine were limited in life by the decay characteristics of the applied magnetic field and not by the n = 2 rotational instability.

• Research Organization: Pennsylvania State Univ., University Park (USA)
• OSTI ID: 6842824
• 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
ELECTRON TUBES
GAS DISCHARGE TUBES
LIFETIME
PINCH EFFECT
PLASMA DIAGNOSTICS
PRODUCTION
REVERSE-FIELD PINCH
THETA PINCH
TORI