Departures from local thermodynamic equilibrium in cutting arc plasmas derived from electron and gas density measurements using a two-wavelength quantitative Schlieren technique

Journal Article · Tue Mar 15 00:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3552304· OSTI ID:21538158

Prevosto, L; Mancinelli, B ^[1]; Artana, G ^[2]; Kelly, H ^[1]

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1. Grupo de Descargas Electricas, Departamento Ing. Electromecanica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto 2600, Santa Fe (Argentina)
2. Laboratorio de Fluidodinamica, Departamento Ing. Mecanica, Facultad de Ingenieria (UBA), Paseo Colon 850, C1063ACV, Buenos Aires (Argentina)

A two-wavelength quantitative Schlieren technique that allows inferring the electron and gas densities of axisymmetric arc plasmas without imposing any assumption regarding statistical equilibrium models is reported. This technique was applied to the study of local thermodynamic equilibrium (LTE) departures within the core of a 30 A high-energy density cutting arc. In order to derive the electron and heavy particle temperatures from the inferred density profiles, a generalized two-temperature Saha equation together with the plasma equation of state and the quasineutrality condition were employed. Factors such as arc fluctuations that influence the accuracy of the measurements and the validity of the assumptions used to derive the plasma species temperature were considered. Significant deviations from chemical equilibrium as well as kinetic equilibrium were found at elevated electron temperatures and gas densities toward the arc core edge. An electron temperature profile nearly constant through the arc core with a value of about 14000-15000 K, well decoupled from the heavy particle temperature of about 1500 K at the arc core edge, was inferred.

• OSTI ID: 21538158
• Journal Information: Journal of Applied Physics, Vol. 109, Issue 6; Other Information: DOI: 10.1063/1.3552304; (c) 2011 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCURACY
ATOMIC FORCE MICROSCOPY
AXIAL SYMMETRY
CONDENSATES
DENSITY
ELECTRIC ARCS
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELECTRONS
ENERGY DENSITY
EQUATIONS OF STATE
FLUCTUATIONS
ION TEMPERATURE
LTE
PARTICLES
PLASMA
PLASMA DENSITY
SAHA EQUATION
THERMODYNAMICS
WAVELENGTHS
CURRENTS
ELECTRIC CURRENTS
ELECTRIC DISCHARGES
ELEMENTARY PARTICLES
EQUATIONS
EQUILIBRIUM
FERMIONS
LEPTONS
MICROSCOPY
PHYSICAL PROPERTIES
SYMMETRY
VARIATIONS