A uniform glow discharge plasma source at atmospheric pressure

Abstract

An atmospheric-pressure, uniform, continuous, glow plasma was produced in ambient air assisted by argon feeding gas, using a 13.56 MHz rf source. Based on the measured current–voltage curve and optical emission spectrum intensity, the plasma showed typical glow discharge characteristics, free from streamers and arc. The measured rotational and vibrational temperatures were in the range of 490 to 630 K and 2000 to 3300 K, respectively, within the operation range of argon flow rate and rf power. From the spatial measurement of total optical emission intensity, and rotational and vibrational temperatures, the plasma shows very high uniformity (over 93%) in the lengthwise direction. The plasma size for this study was 200 mm×50 mm×5 mm, although a plasma was produced in the scaled-up version of 600 mm in length, aiming for large-area plasma applications.

Mode Characteristics of radio-frequency atmospheric glow discharges

“…At lowcurrent densities, the discharge current increases in proportion to the RF voltage across the electrode gap and the differential conductivity of the plasma is positive. This is similar to the mode in low-pressure glow discharges, and corresponds to the operation regime of most reported RF APGD experiments [1]- [7], [9], [16]. When the current density increases to a critical threshold, the discharge plasma evolves into a different operation regime in which the discharge current increases with decreasing gap voltage and the differential conductivity becomes negative [8].…”

“…Their operation is also very versatile, helped partly by their low-breakdown voltage. Through largely an engineering development, their application range and capability have been expanded considerably [1], [6], [9]. Yet there is a fundamental need for substantially advancing their basic understanding in order to aid not only the interpretation of complex experimental observations but also the development of their diagnostics methodologies.…”

“…A TMOSPHERIC pressure glow discharges (APGD) generated at radio frequencies (RF) at megahertz are used increasingly for many technologically important applications including etching, deposition, surface modification, and decontamination [1]- [9]. They are capacitively coupled plasmas generated usually between two bare metallic electrodes and typically at 13.56 MHz.…”

A review of plasma–liquid interactions for nanomaterial synthesis

“…The recently developed plasma arrays [22,[319][320][321][322][323][324] might be a good choice since the plasma area is much increased by integrating many microplasmas into one array. We can also use other large-area atmospheric-pressure plasmas [325][326][327][328][329][330][331][332][333] which are based on different designs.…”

Contrasting characteristics of pulsed and sinusoidal cold atmospheric plasma jets

“…Often this is realized in a jetlike configuration. [2][3][4][5][6][7][8][9][10][11] The vast majority of APGD jets reported so far employ sinusoidal excitation, although it has been known that nonsinusoidal excitation, through voltage pulsing, for example, offers a useful freedom to further improve APGD performance. 12 Initial results from few reported studies of pulsed APGD jets 4,10,13 have shown their general similarity to and contrast with sinusoidal APGD jets.…”