Measurement of ion flows using an unmagnetized'' Mach probe in the interchangeable module stellarator

Journal Article · Mon Aug 01 04:00:00 EDT 1994 · Review of Scientific Instruments; (United States)

DOI:https://doi.org/10.1063/1.1144658· OSTI ID:7014241

Peterson, B J; Talmadge, J N; Anderson, D T; Anderson, F S.B.; Shohet, J L ^[1]

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1. Torsatron-Stellarator Laboratory, Department of Electrical and Computer Engineering, University of Wisconsin---Madison, Madison, Wisconsin 53706 (United States)

A Mach probe is used to measure poloidal and toroidal flows induced by a biased electrode in IMS. Mach probe theories are reviewed and classified as either magnetized or unmagnetized. A simple geometric model of the IMS Mach probe shows that the variation of the effective probe area as a function of the probe orientation with respect to the magnetic field is 20%--25%, predicting the probe to be only slightly magnetized. Measurements of the variation in the total ion saturation current collected by the probe, as the angle with respect to the magnetic field is varied, demonstrate this level of magnetization only at low neutral pressure at large minor radius, while in other cases the variation in the total collected current is negligible. Based on this result an unmagnetized model [M. Hudis and L. M. Lidsky, J. Appl. Phys. [bold 41], 5011 (1970)] is chosen to analyze the IMS Mach probe data. Comparison of Mach probe poloidal flow measurements as a function of minor radius to calculations of the [bold E][times][bold B] drift velocity and the ion diamagnetic drift velocity from radial profiles of floating potential and ion saturation current, respectively, shows agreement to within 15%.

• DOE Contract Number: FG02-93ER54222
• OSTI ID: 7014241
• Journal Information: Review of Scientific Instruments; (United States), Journal Name: Review of Scientific Instruments; (United States) Vol. 65:8; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700320* -- Plasma Diagnostic Techniques & Instrumentation-- (1992-)
CHARGED PARTICLES
CHARGED-PARTICLE TRANSPORT
CLOSED PLASMA DEVICES
IMS STELLARATOR
IONS
MAGNETIC FIELDS
PROBES
RADIATION TRANSPORT
STELLARATORS
THERMONUCLEAR DEVICES
VELOCITY