Filtered Thomson Scattering in an Argon Plasma

Abstract

A ltered Thomson scattering technique has been developed to measure electron temperature T e and electron number density n e in an atmospheric pressure argon plasma.The problems of the strong background scattered light and the high plasma luminosity were resolved by employing an atomic vapor lter that provided strong attenuation of stray scattered light at the laser wavelength while simultaneously allowing the passage of the spectrally broad Thomsonscattered light. A relatively low-power Ti: sapphire laser (about 50 mJ/pulse) was used in conjunction with an optically thick rubidium notch ler. High spectral purity of the laser was achieved by developing an ampli ed stimulated emission lter. Because of the geometrical constraints of the plasma arc source, experiments were performed in the backscatter geometry. Information on the electron number density and the electron temperature was derived from the Thomson signal by tting a model curve to the data. The measurement results gave an electron temperature of 0:82 § § 0:06 eV and electron number density of 1:61 £ £ 10 16 § § 0:05 £ £ 10 16 electrons/cm 3 .

Avoiding solid carbon deposition in plasma-based dry reforming of methane

“…The large error bars are ascribed to the overlap with the Rayleigh peak and the stray light that are cut from the spectra with a notch filter. 36,37…”

Localized time accurate sampling of nonequilibrium and unsteady hypersonic flows: methods and horizons

“…The narrowing of the scattering in the forward direction enables the selective narrowing of the Thomson scattering relative to the Raman lines and thus the separation of the Thomson from the Raman. The Rayleigh/Brillouin scattering and ion Thomson scattering are also narrowed by the same process, so inserting an atomic filter and tuning the illumination laser to the atomic filter absorption feature eliminates the Rayleigh/Brillouin and ion Thomson scattering and passes the Raman and electron Thomson scattering (Zaidi et al 2002;Lee and Lempert 2002). The spectrum can then be analyzed by passing that light into a spectrometer.…”