metastable level density and temperature measurement in a low-density argon plasma

Abstract

Temperature and density measurements of the 4s 3 P 2 argon metastable atom level in a weakly diffusion ionized argon plasma are presented and discussed. The steady state collisionless unmagnetized plasma is generated at a gas pressure of 50 mPa, extruded by hot filament DC discharges and diffused in a chamber of about 40 l volume. The temperature is measured from the absorption linewidth and the density from the spectral absorption coefficient of a low-cost single-mode diode laser (801 479 nm) by scanning its frequency around the 4s 3 P 2 -4p 3 D 2 ArI transition.

Anomalous evolution of Ar metastable density with electron density in high density Ar discharge

“…[12][13][14] There have been a number of experiments and theoretical calculations especially on argon atom metastable states (1s 3 and 1s 5 in Paschen notation) density with regard to plasma power or pressure. In experiments, various techniques such as laser induced fluorescence (LIF), [15][16][17][18] laser absorption spectroscopy (LAS), 16,[19][20][21][22][23][24][25] and optical emission spectroscopy (OES) (Refs. [26][27][28][29] were used to measure 1D or 2D distribution of metastable density.…”

Absorption spectroscopy measurements of resonant and metastable atom densities in atmospheric-pressure discharges using a low-pressure lamp as a spectral-line source and comparison with a collisional-radiative model

“…The density of metastable and resonant atoms can be determined in various ways: self-absorption [7][8][9][10][11] and absorption using the emission from a tunable diode laser [12][13][14][15][16][17][18] or the line from a spectral lamp [2,[19][20][21][22][23][24][25][26][27]. Utilizing lasers to determine the density of metastable and resonant atoms is advantageous, as it does not depend on the absorption-line spectral profile.…”

Mathematical Modelling of RF Plasma Flow at Low Pressures with 3D Electromagnetic Field

“…It is known that excited atoms (metastable) are essential for the balance of particles and energies in RF discharges in argon [18][19][20][21][22]. e spatial distribution of metastable particles in the jet of an inductive coupled RF at low pressure was studied in [15].…”