Open AccessCavity-enhanced Thomson scattering measurements of electron density and temperature in a hollow cathode discharge
Author(s) -
Adam Friss,
Azer P. Yalin
Publication year - 2018
Publication title -
optics letters/optics index
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.524
H-Index - 272
eISSN - 1071-2763
pISSN - 0146-9592
DOI - 10.1364/ol.43.005343
Subject(s) - thomson scattering , materials science , plasma , optics , electron temperature , electron density , plasma diagnostics , scattering , atomic physics , laser , cathode ray , power density , electron , physics , power (physics) , quantum mechanics
A cavity-enhanced Thomson scattering (CETS) diagnostic has been developed to perform electron density and temperature measurements in low-density weakly ionized discharges. The diagnostic approach is based on generating a high-power beam in an optical build-up cavity and using the beam as a light source for Thomson scattering from plasma housed within the cavity. In our setup, a high-power (∼5 W) fiber laser at 1064 nm allows an intra-cavity power of 11.7 kW in a two-mirror cavity for measurements in the plume of a BaO hollow cathode discharge. A study of plasma density and temperature was performed at various operating conditions. Electron densities and temperatures in the range of ∼10 12 cm -3 and ∼3 eV were measured, respectively. The high signal-to-noise ratio (SNR) of the present measurements (SNR=1100) suggests the ability to measure significantly lower density plasmas in the range of ∼3×10 9 to 3×10 10 cm -3 , thereby extending current laser Thomson scattering diagnostic capabilities.