On the green aurora emission of Ar atmospheric pressure plasma

Abstract

The Ar atmospheric pressure plasma was found to be an excellent laboratorial source for green aurora emission. However, the characteristic and production mechanism of the green aurora emission of the Ar atmospheric pressure plasma are still not clear. In this paper, an Ar plasma in a long glass tube which emits intense green aurora light is investigated. With the long glass tube, it can be concluded that the green aurora emission in the Ar plasma is not owing to the mixture of Ar plasma plume with the surrounding air. It is also found that the green aurora emission often appeared beyond the active electrode when the active electrode is placed at the downstream of the gas flow. The green emission disappears when the traces amount of O2 or N2 (about 0.05%-0.07%) is added to Ar. This is because the O2 molecules deactivate the upper state O1S, which results in the decrease of the green emission. On the other hand, when N2 is added, Ar metastable atoms are quenched by N2, which results in the decrease of O atoms and eventually lead to the decrease of the green emission intensity. The intensity of the green aurora emission increases when the driving voltage frequency increases from 1 kHz to 10 kHz. More importantly, it is found that the green aurora emission is not affected when a grounded stainless steel needle is in contacted with the plasma plume. Thus, the green emission is not driven electrically. All these findings are helpful for the understanding of the physics and its applications of APPJ in space physics, laser physics and other application areas.

Characterization of an atmospheric pressure plasma jet producing the auroral transition O(1S) to O(1D)

“…Such measurements are lacking mostly due to the requirements and difficulty of laser based techniques such as Thomson scattering. A quantitative measurement of the EEPF is required to clearly understand the role of electrons in the formation of O( 1 S) which was not done in previous studies focusing on this topic [18,24,25]. The plasma parameters (n e and T e ) which dictates the intensity of O( 1 S) was also missing in these studies.…”

“…However, the spectral resolution was poor and it was not clear what reactions and species were definitively present. Recent work demonstrated a clear signal of the O( 1 S)−O( 1 D) transition along with detection of ON 2 excimers based on the spectral lineshape [18,24,25]. A set of reactions to create O( 1 S) has been discussed previously [10,26,27] that first relies on the creation of metastable nitrogen (N 2 A 3 Σ + u ).…”

Transition from a filamentary mode to a diffuse one with varying distance from needle to stream of an argon plasma jet

“…[1] More importantly, other than in a confined gap between electrodes, the plasma jet can emanate a remote plasma plume abundant with active species in open space. [2,3] Hence, the plasma jet has been extensively used in various application fields, including material synthesis, [4] surface modification, [5,6] ozone generation, [7] water purification, [8] pollutant degradation, [9] methane conversion, [6] light source, [10] sterilization, [11,12] catalysis, [13] and biomedicine, [14] etc.…”

Discharge aspects of a snake‐like plasma plume generated by an atmospheric pressure plasma jet with variable argon flow rate

“…[1,2] The produced plasma in air ambient is also called a plasma plume, [3][4][5][6] in which there are abundant active species. [7] Due to its flexibility and low cost, plasma jet has become a promising tool for the applications in biomedicine, [8,9] material synthesis, [10][11][12] surface modification, [13][14][15] light source, [16] and water purification. [17][18][19] Plasma jet is normally fed with inert gas, such as helium, [20][21][22] argon, [23][24][25][26] neon, [27][28][29] and so on.…”

“…[ 1,2 ] The produced plasma in air ambient is also called a plasma plume, [ 3–6 ] in which there are abundant active species. [ 7 ] Due to its flexibility and low cost, plasma jet has become a promising tool for the applications in biomedicine, [ 8,9 ] material synthesis, [ 10–12 ] surface modification, [ 13–15 ] light source, [ 16 ] and water purification. [ 17–19 ]…”