Influence of flowing helium gas on plasma plume formation in atmospheric pressure plasma

Abstract

We have studied atmospheric pressure plasma generated using a quartz tube, helium gas, and a foil electrode by applying RF high voltage. The atmospheric pressure plasma in the form of a bullet is released as a plume into the atmosphere. The helium gas flowing out of quartz tube mixes with air, and the flow channel is composed of the regions of flowing helium gas and air. The plasma plume length is equivalent to the reachable distance of flowing helium gas. Although the amount of helium gas on the flow channel increases by increasing the inner diameter of quartz tube at the same gas flow velocity, the plasma plume length peaks at around 8 m/s of gas flow velocity, which is the result that a flow of helium gas is balanced with the amount of gas. The plasma plume is formed at the boundary region where the flow of helium gas is kept to the wall of the air. V C 2015 AIP Publishing LLC. [http://dx.

Time Behaviour of Helium Atmospheric Pressure Plasma Jet Electrical and Optical Parameters

“…We were able to point in this way that, for constant flow rate conditions and fixed electrode arrangement, the length of the outside jet depends on the frequency and amplitude of the driving high voltage pulses ( Figure 6). Supplementary, it has been demonstrated in a number of recent studies, that this characteristic dimension of the outside plasma jets in helium is also influenced by the electrodes dimensions and constructive details [40,41], gas flow rate [38,[42][43][44], dielectric tube diameter [45][46][47].…”

Effect of the angle between the electric field and the gas flow one on the plasma plume dynamics at atmospheric pressure

“…利用 双环电极结构, Karakas等人 [19] 研究了平行场射流的放 电特性. Walsh等人 [18] [15,[20][21][22] . 利用单针结构的射流, Wu等人 [15] 研究发现上游羽产生的电子、离子及亚稳态粒子可 以影响下游羽的传播 下的电离波传播 [14][15][16][17] , 即放电对应着流光过程 [23] .…”

Dynamics of Atmospheric Pressure Plasma Plumes in the Downstream and Upstream Regions

“…From the view point of the plume dynamics, the propagation behaviors of the plasma bullets have been extensively investigated in the downstream and intra‐electrode regions . However, the plasma plume can also be generated in the upstream region besides the downstream region . In fact, the upstream plume has a great influence on the downstream one, which results from the meta‐stable atoms produced in the upstream region .…”

“…Up to now, the characteristics of the APNPJs have been investigated for various discharges, such as hollow cathode discharge, [8,9] dielectric-barrier discharge, [10][11][12] micro-discharge [13,14] and corona discharge. [15,16] To better understand the discharge dynamics of the jets, high-speed images captured by an intensified charge-coupled device (ICCD) with nanosecond exposure time indicate that the plasma plumes are not continuous but composed of fast-moving plasma bullets, which are first reported by Teschke et al [17] From then on, a variety of plasma jets have been designed to investigate the dynamics of the plasma plumes, [18][19][20][21][22][23][24] which reveals that the propagating bullet in the range of 10 3 À10 5 m Á s À1 is several orders of magnitude faster than the gas flow.…”

“…[18][19][20][21][22][23][24][25][26][27][28][29][30][31] However, the plasma plume can also be generated in the upstream region besides the downstream region. [11,31] In fact, the upstream plume has a great influence on the downstream one, which results from the meta-stable atoms produced in the upstream region. [32] Using two single-needle jets excited by sub-microsecond pulse voltage, Wu et al have found that the active species generated by the upstream plume can enhance the propagation of the downstream plume and both the plumes propagate in a snake-like motion caused by a turbulent gas flow.…”