Measurement of thermal plasma jet temperature and velocity by laser light lineshape analysis

Conference · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5700551

Snyder, S C; Reynolds, L D

Two important parameters of thermal plasma jets are kinetic or gas temperatures and flow velocity. Gas temperatures have been traditionally measured using emission spectroscopy, but this method depends on either the generally unrealistic assumption of the existence of local thermodynamic equilibrium (LTE) within the plasma, or the use of various non-LTE or partial LTE models to relate the intensity of the emission lines to the gas temperature. Plasma jet velocities have been measured using laser Doppler velocimetry on particles injected into the plasma. However, this method is intrusive and it is not known how well the particle velocities represent the gas velocity. Recently, plasma jet velocities have been measured from the Doppler shift of laser light scattered by the plasma. In this case, the Doppler shift was determined from the difference in the transmission profile of a high resolution monochromator between red shifted and blue shifted scattered light. A direct approach to measuring localized temperatures and velocities is afforded by high resolution scattered light lineshape measurements. The linewidth of laser light scattered by atoms and ions can be related to the kinetic temperature without LTE assumptions, while a shift in the peak position relative to the incident laser lineshape yields the gas velocity. We report in this paper work underway to measure gas temperatures and velocities in an argon thermal plasma jet using high resolution lineshape analysis of scattered laser light.

• Research Organization: EG and G Idaho, Inc., Idaho Falls, ID (USA)
• Sponsoring Organization: DOE; USDOE, Washington, DC (USA)
• DOE Contract Number: AC07-76ID01570
• OSTI ID: 5700551
• Report Number(s): EGG-M-91017; CONF-910711--1; ON: DE91010053
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
DOPPLER BROADENING
ELECTROMAGNETIC RADIATION
ELEMENTS
EQUILIBRIUM
FABRY-PEROT INTERFEROMETER
FLUIDS
GASES
INTERFEROMETERS
JETS
LASER RADIATION
LIGHT SCATTERING
LINE BROADENING
MEASURING INSTRUMENTS
NONMETALS
PLASMA
RADIATIONS
RARE GASES
SCATTERING
TEMPERATURE MEASUREMENT
THERMAL EQUILIBRIUM
VELOCIMETERS