Studies of global stability of field-reversed configuration plasmas using a rigid body model
- 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, Vol. 5, Issue 10; Other Information: PBD: Oct 1998
- Country of Publication:
- United States
- Language:
- English
Similar Records
Ion Rings for Magnetic Fusion
Principal physics of rotating magnetic-field current drive of field reversed configurations