Studies of global stability of field-reversed configuration plasmas using a rigid body model

Journal Article · Thu Oct 01 04:00:00 EDT 1998 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.872978· OSTI ID:658487

Ji, H; Yamada, M; Kulsrud, R; Pomphrey, N; Himura, H ^[1]

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1. Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)

Global stability of field-reversed configuration (FRC) plasmas has been studied using a simple rigid body model in the parameter space of {ital s} (the ratio of the separatrix radius to the average ion gyro-radius) and plasma elongation {ital E} (the ratio of the separatrix length to the separatrix diameter). Tilt stability is predicted, independent of {ital s}, for FRC{close_quote}s with low {ital E} (oblate), while the tilt stability of FRC{close_quote}s with large {ital E} (prolate) depends on s/E. It is found that plasma rotation due to ion diamagnetic drift can stabilize the tilt mode when s/E{approx_lt}1.7. The so-called collisionless ion gyro-viscosity also is identified to stabilize tilt when s/E{approx_lt}2.2. Combining these two effects, the stability regime broadens to s/E{approx_lt}2.8, consistent with previously developed theories. A small additional rotation (e.g., a Mach number of 0.2) can improve tilt stability significantly at large {ital E}. A similar approach is taken to study the physics of the shift stability. It is found that radial shift is unstable when E{lt}1 while axial shift is unstable when E{gt}1. However, unlike tilt stability, gyro-viscosity has little effect on shift stability. {copyright} {ital 1998 American Institute of Physics.}

• OSTI ID: 658487
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 10 Vol. 5; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
FIELD-REVERSED THETA PINCH DEVICES
PLASMA CONFINEMENT
PLASMA INSTABILITY
ROTATION
VISCOSITY