Supersonic gas injector for fueling and diagnostic applications on the National Spherical Torus Experiment

Journal Article · Fri Oct 01 00:00:00 EDT 2004 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.1787579· OSTI ID:20641306

Soukhanovskii, V A; Kugel, H W; Kaita, R; Majeski, R; Roquemore, A L ^[1]

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1. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

A prototype pulsed supersonic gas injector (SGI) has been developed for the National Spherical Torus Experiment (NSTX). Experiments in NSTX will explore the compatibility of the supersonic gas jet fueling with the H-mode plasma edge, edge localized mode control, edge magnetohydrodynamic stability, radio frequency heating scenarios, and start-up scenarios with a fast plasma density ramp up. The diagnostic applications include localized impurity gas injections for transport and turbulence experiments and edge helium spectroscopy for edge T{sub e} and n{sub e} profile measurements. Nozzle and gas injector design considerations are presented and four types of supersonic nozzles are discussed. The prototype SGI operates at room temperature. It is comprised of a small graphite Laval nozzle coupled to a modified commercial piezoelectric valve and mounted on a movable vacuum feedthrough. The critical properties of the SGI jet - low divergence, high density, and sharp boundary gradient, achievable only at M>1, have been demonstrated in a laboratory setup simulating NSTX edge conditions. The Mach numbers of about 4, the injection rate up to 10{sup 22} particles/s, and the jet divergence half angle of 6 deg. have been inferred from pulsed pressure measurements.

• OSTI ID: 20641306
• Journal Information: Review of Scientific Instruments, Vol. 75, Issue 10; Conference: 15. topical conference on high temperature plasma diagnostics, San Diego, CA (United States), 19-22 Apr 2004; Other Information: DOI: 10.1063/1.1787579; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
EDGE LOCALIZED MODES
GAS INJECTION
GRAPHITE
H-MODE PLASMA CONFINEMENT
HELIUM
MACH NUMBER
MAGNETOHYDRODYNAMICS
NOZZLES
NSTX DEVICE
PIEZOELECTRICITY
PLASMA
PLASMA DIAGNOSTICS
PLASMA IMPURITIES
PLASMA JETS
PRESSURE MEASUREMENT
RADIOWAVE RADIATION
RF SYSTEMS
SPECTROSCOPY
SUPERSONIC FLOW
VALVES