Ion heating and magnetohydrodynamic dynamo fluctuations in the reversed‐field pinch

• Published in: Physics of fluids. B, Plasma physics Plasma physics, 1992-12, Vol.4 (12), p.4062-4071
• Main Authors: Scime, Earl, Cekic, Miodrag, Den Hartog, D. J., Hokin, Samuel, Holly, D. J., Watts, Christopher
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 700370 > Plasma Fluid & MHD Properties-- (1992-); COLLISIONS; ELECTRON COLLISIONS; ELECTRON-ION COLLISIONS; Exact sciences and technology; FLUCTUATIONS; FLUID MECHANICS; HEATING; HYDRODYNAMICS; ION COLLISIONS; ION TEMPERATURE; MAGNETOHYDRODYNAMICS; MECHANICS; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; PINCH EFFECT; PLASMA HEATING; Plasma production and heating; REVERSE-FIELD PINCH; VARIATIONS 700350 > Plasma Production, Heating, Current Drive, & Interactions-- (1992-)
• ISSN: 0899-8221; 2163-503X
• DOI: 10.1063/1.860313

Ion temperatures have been measured in the Madison Symmetric Torus (MST) [Dexter et al., Fusion Technol. 19, 131 (1991)] reversed‐field pinch (RFP) with a five channel charge exchange analyzer. The characteristic anomalously high ion temperature of RFP discharges has been observed in the MST. The ion heating expected from ion–electron collisions is calculated and shown to be too small to explain the measured ion temperatures. The charge exchange determined ion temperature is also compared to measurements of the thermally broadened Cv 227.1 nm line. The ion temperature, T i ≊250 eV for I=360 kA, increases by more than 100% during discrete dynamo bursts in MST discharges. Magnetic field fluctuations in the range 0.5–5 MHz were also measured during the dynamo bursts. Structure in the fluctuation frequency spectrum at the ion cyclotron frequency suggests that the mechanism of ion heating involves the dissipation of dynamo fluctuations at ion cyclotron frequencies.