Study on discharge mode and transition mechanism of atmospheric pressure Ar/Zn pulsed microwave plasma jet

Abstract

The microwave plasma jet has the advantage of high plasma density and abundant active particles but fails to produce large-scale microwave plasmas in ambient air which hinders the application of microwave plasma ignition and combustion. We have applied a surface wave resonator (including a Zn-coated iron wire trigger) to produce a large-scale Ar/Zn pulsed microwave plasma jet. The discharge experiment shows that the plasma jet generally presents three discharge modes, namely, filamentous argon discharge (P < 120 W), bright argon plasma filaments covered by Ar/Zn thin plasma layers (120 W ≤ P ≤ 150 W), and bright thick Ar/Zn plasma columns (P ≥ 155 W). The optical emission spectrum indicates that the electron temperature is ∼4000–5000 K, the electron density is on the order of 1015 cm−3, and the plasma has the characteristic of local thermodynamic equilibrium. According to the transient discharge photos and the simulated electric fields, the mechanism of the three discharge modes and their transformations could be attributed to the combined interactions (the mutual resonance enhancement between the surface wave and the plasma jet, the propagation of the ionization wave, and the different particle states in the Ar/Zn pulsed microwave plasma). The results have suggested that the large-scale Ar/Zn pulsed microwave plasma jet can be generated by adding Zn vapor into the Ar microwave plasma jet and the proposed Ar/Zn pulsed microwave plasma jet is suitable for the application of plasma ignition and combustion.

Study of spatiotemporal characteristics of atmospheric-pressure pulsed microwave Ar/N<sub>2</sub> plasma jets

“…(1) 如下所示: 辐射增强现象. 这是因为脉冲功率消失, 趋肤效应消 失 [7] , 等离子体射流外部的高能电子汇聚到射流内部, 在电子移动的过程中与Ar/N 2 气体分子频繁地发生碰 撞, 碰撞过程产生了更多的热电子和激发态粒子, 增强 了等离子体射流的光辐射, 此后热电子逐渐消失, 激发 态粒子也退激发而逐渐消失 [43,44] . 量级) [45] .…”

Development of an atmospheric fluorocarbon plasma jet generated by pulse modulated microwave discharge

“…The whole experimental setup consists of three parts: the power supply, the discharge device and the working gases system. A homemade pulse modulated microwave source is utilized as the power supply (output power: 0-200 W, microwave frequency: 2.45 GHz, pulse frequency: 10 Hz-200 kHz, duty cycle: 0.01-0.99), for which the main composition can be found in the [18]. All the input microwave powers in this work refer to the peak power.…”

Ionization behavior of hairpin argon plasma jets resonantly generated by microwave pulses at atmospheric pressure

“…J K Lee 课题组 [8] 发现微波放电射流随气体 成分和微波频率的改变表现出不同的形态. 陈兆权等人 [13,14,[21][22][23] 性相反 [12,18,24] . 将发卡尖端削尖至 0.05 mm, 以便更容易触发放电.…”