Study of the magnetic-field evolution in the spheromak merging experiment

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5503842

Kawai, K

Merging of two nearly identical spheromaks was attained to study plasma relaxation during the evolution from the two-spheromak configuration to a final single configuration. Two opposing conical theta pinches were utilized to produce spheromaks, which were then ejected into a flux-conserving confinement section with external fields imbedded. The two merging spheromaks were given parallel poloidal fields and opposite toroidal fields; the total helicity of the two spheromak system, therefore, was designed to be nearly zero. The magnetic field evolution during merging was investigated by a large array of internal magnetic field probes. Two-dimensional field mapping was performed to describe the evolution. Reconnection of the two poloidal fields was completed in approximately 2 {mu}sec, while annihilation of the toroidal fields occurred relatively slowly, in about 10 {mu}sec. Observations suggested that the plasma relaxation in this merging process occurred on the diffusion time scale rather than Alfven transit times, and that the plasma did not evolve to a force-free state. The slow relaxation is attributed to a global structural change (small k value) associated with the merging configuration.

• Research Organization: Washington Univ., Seattle, WA (USA)
• OSTI ID: 5503842
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
700103 -- Fusion Energy-- Plasma Research-- Kinetics
CLOSED PLASMA DEVICES
CONFINEMENT
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC PROBES
MAGNETIC RECONNECTION
PLASMA CONFINEMENT
PROBES
RELAXATION TIME
SPHEROMAK DEVICES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES