Magnetic reconnection in field-reversed configurations
Internal magnetic field probes are used to study the magnetic field-line reconnection during the formation of field-reversed configurations (FRC's) in a low-compression theta-pinch. Measurements of the reversed trapped flux indicated that most of the loss of the initial bias flux occurs during the radial implosion. Therefore, the flux loss is not a consequence of plasma-wall contact during field-reversal. An operating boundary in the parameter space of filling pressure, bias field, and external field is found for formation of FRC's with equilibrium lengths shorter than the coil. Measurements of the internal magnetic fields near the ends of the theta-pinch indicate that FRC formation can be delayed by plasma flow out the ends. The addition of independently driven magnetic mirrors extends the operating boundary. An axial array of magnetic islands forms during the early stages of the discharge. These islands then coalesce into large units. Several possible explanations of their formation are given. In addition, the growth rate for coalescence obtained from MHD simulations is compared with the experimental results. With the addition of a third magnetic mirror near the midplane of the device the formation of a two-cell FRC is observed.
- Research Organization:
- Washington Univ., Seattle (USA)
- OSTI ID:
- 5816770
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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