Axial dynamics in field-reversed theta pinches. II: Stability

Journal Article · Tue Oct 01 00:00:00 EDT 1991 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860000· OSTI ID:5147948

Tuszewski, M; Taggart, D P; Chrien, R E; Rej, D J; Siemon, R E; Wright, B L ^[1]

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1. Los Alamos National Laboratory, Los Alamos, New Mexico (USA)

Detailed stability studies are made with new diagnostics in the FRX-C/LSM field-reversed theta pinch (Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1989), Vol. II, p. 517). These studies seek the origin of a degradation of the confinement properties of field-reversed configurations (FRC's) that appears associated with strong axial dynamics during plasma formation. Several instabilities are observed, including rotational modes, interchanges, and tilt instabilities. Only the latter are strongly correlated with FRC confinement. Tilt instabilities are observed for FRC's with larger average number of ion gyroradii ({ital s}{similar to}3--5) and smaller separatrix elongations ({ital e}{similar to}3--4). Coincidently, strong axial dynamics occurs for cases with larger {ital s} and smaller {ital e} values, through increases in either reversed bias field or fill pressure. These data provide some understanding of FRC stability. In agreement with finite Larmor radius theory, there is a regime of gross stability for the very kinetic and elongated FRC's with {ital s}/{ital e}{lt}0.2--0.3. This is the regime that has been studied in most FRC experiments. However, tilt and other instabilities are observed for FRC's with {ital s}/{ital e}{similar to}1. Additional stabilization techniques will be required for future large-size FRC's.

• OSTI ID: 5147948
• Journal Information: Physics of Fluids B; (United States), Vol. 3:10; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA CONFINEMENT
INHIBITION
THETA PINCH
STABILITY
AXIAL SYMMETRY
DYNAMICS
FLUTE INSTABILITY
IMPLOSIONS
MAGNETIC FIELD REVERSAL
PLASMA DIAGNOSTICS
ROTATION
THERMONUCLEAR REACTIONS
TILTING INSTABILITY
CONFINEMENT
INSTABILITY
MAGNETIC FIELD CONFIGURATIONS
MECHANICS
MOTION
NUCLEAR REACTIONS
NUCLEOSYNTHESIS
PINCH EFFECT
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
SYMMETRY
SYNTHESIS
700107* - Fusion Energy- Plasma Research- Instabilities
700103 - Fusion Energy- Plasma Research- Kinetics