Gas mixing enhanced by power modulations in atmospheric pressure microwave plasma jet

Abstract

Microwave plasma jet operating in atmospheric pressure argon was power modulated by audio frequency sine envelope in the 10 2 W power range. Its efluent was imaged using interference ilters and ICCD camera for several different phases of the modulating signal. The combination of this fast imaging with spatially resolved optical emission spectroscopy provides useful insights into the plasmachemical processes involved. Phase-resolved schlieren photography was performed to visualize the gas dynamics. The results show that for higher modulation frequencies the plasma chemistry is strongly inluenced by formation of transient low perturbation resembling a vortex during each period. The perturbation formation and speed are strongly inluenced by the frequency and power variations while they depend only weakly on the working gas low rate. From application point of view, the perturbation presence signiicantly broadened lateral distribution of active species, effectively increasing cross-sectional area suitable for applications.

On the transition of reaction pathway during microwave plasma gas‐phase synthesis of graphene nanosheets: From amorphous to highly crystalline structure

“…The rotational temperatures T g were estimated by fitting experimentally obtained CN (B 2 ∑ + −X 2 ∑ + ) band at 388.3 nm using simulation by the MassiveOES software. [ 30 ] These temperatures could be used to approximate the neutral gas temperature due to the fact that collision rates in the plasma at atmospheric pressure conditions are high enough to ensure local thermodynamic equilibrium.…”

An atmospheric pressure non‐self‐sustained glow discharge in between metal/metal and metal/liquid electrodes

“…Four vibrational peaks of a second positive system of nitrogen N 2 C 3 П u →B 3 П g (Δ v = 0–2, 1–3, 2–4, and 3–5) were fitted with the use of MassiveOES to obtain both T vib and T rot of N 2 excited states. An example of the fitting result for a case of the metal additional electrode at the discharge current of 12 mA is presented in Figure .…”

“…Intensities of vibrational sequence Δ ν = 2, 0–2 (head maximum 380.4 nm), 1–3 (375.4 nm), 2–4 (370.9), and 3–5 (367.1 nm) were recorded to obtain temperature T vib . MassiveOES software was used to fit N 2 C 3 П u →B 3 П g experimental and theoretical spectra, providing T rot and T vib as a result of the fitting process. The discharge emission was collected with ceramics ferrule fiber ( d = 200 μm) allowing spatially resolved measurement in three different positions with a 2‐mm diameter of the collecting region (cathode area, positive column, and anode area) as shown in Figure (see Section 3.1).…”

On the electron density of atmospheric pressure radio frequency dielectric barrier discharge and discharge with bare electrode

“…Gas temperature was estimated by measuring the rotational temperature of OH(A) excited states-a method commonly used in low temperature plasma [23][24][25][26] . The OH (A 2 Σ + → Χ 2 Π, 0-0) bands in the range of 306-312 nm is recorded and fitted using massiveOES software 27) . This software was described and successfully applied to calculate the gas temperature in previous research 26,28) .…”