Soft x‐ray measurement of internal tearing mode structure in a reversed‐field pinch

• Published in: Physics of fluids. B, Plasma physics Plasma physics, 1992-12, Vol.4 (12), p.4019-4022
• Main Authors: Chartas, George, Hokin, Samuel
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 700310 > Plasma Confinement-- (1992-); ANNULAR SPACE; CLOSED CONFIGURATIONS; CLOSED PLASMA DEVICES; CONFIGURATION; CONFINEMENT; ELECTROMAGNETIC RADIATION; Exact sciences and technology; INSTABILITY; IONIZING RADIATIONS; MAGNETIC FIELD CONFIGURATIONS; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; PINCH EFFECT; PLASMA CONFINEMENT; PLASMA INSTABILITY; PLASMA MACROINSTABILITIES; RADIATIONS; RESONANCE; REVERSE-FIELD PINCH; SOFT X RADIATION; SPACE; TEARING INSTABILITY; THERMONUCLEAR DEVICES; TOKAMAK DEVICES; TOROIDAL CONFIGURATION; Waves, oscillations, and instabilities in plasmas and intense beams; X RADIATION 700340 > Plasma Waves, Oscillations, & Instabilities-- (1992-)
• ISSN: 0899-8221; 2163-503X
• DOI: 10.1063/1.860307

The structure of internally resonant tearing modes has been studied in the Madison Symmetric Torus (MST) reversed‐field pinch [Fusion Technol. 19, 131 (1991)] with a soft x‐ray detector system consisting of an imaging array at one toroidal location and several detectors at different toroidal locations. The toroidal mode numbers of dominant m=1 structures are in the range n=5,6,7. The modes propagate with phase velocity v=1−6×106 cm/sec, larger than the diamagnetic drift velocity v d ∼5×105 cm/sec. Phase locking between modes with different n is manifested as a beating of soft x‐ray signals which is strongest near the resonant surfaces of the modes (r/a=0.3–0.5) and exhibits characteristics indicative of nonlinear mode coupling.