Transport, energy balance, and stability of a large field-reversed configuration
- University of Washington, Redmond Plasma Physics Laboratory, Redmond, Washington 98052 (United States)
Experiments have been conducted on the Large s Experiment (LSX) [Phys. Rev. Lett. {bold 69}, 2212 (1992)] field-reversed theta pinch, where plasmas confined in a field-reversed configuration (FRC) have exhibited record energy, particle, and configuration lifetimes. By careful control of the formation process, it was possible to form symmetric, quiescent FRCs with {ital s} values (the number of ion gyroradii from the field null to the separatrix of the FRC) as large as 5. LSX particle confinement showed a strong scaling with {ital s}. The inferred particle diffusivity, {ital D}{sub {ital s}}, at large {ital s} approached {similar_to}2 m{sup 2}/s, which, along with previous experimental results, indicate a favorable {ital D}{sub {ital s}}{similar_to}{ital s}{sup {minus}1/2} scaling. At large {ital s}, both electron and ion cross-field thermal conduction losses become negligible compared to convective losses, with the inferred {chi}{sub {perpendicular}{ital e}}{similar_to}4 m{sup 2}/s, which was near classical values. Data from several diagnostics employed on the LSX device were analyzed to seek correlation between distortions in the plasma shape and the confinement properties of the FRCs formed. No clear correlation between the quality of confinement and distortion was observed. Experiments conducted over a large range of {ital s} (1{lt}{ital s}{lt}8) appeared to be grossly stable to low-order modes, such as the internal tilt. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.
- OSTI ID:
- 165301
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 6 Vol. 2; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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