Electrical breakdown characteristics of an atmospheric pressure rf capacitive plasma source

Abstract

Articles you may be interested inDevelopment of a diffuse air-argon plasma source using a dielectric-barrier discharge at atmospheric pressureThe electrical breakdown characteristics of the rf capacitive plasma source are investigated theoretically and experimentally. The plasma source is the electrode type consisting of the concentric cylinders for generating nonequilibrium plasma at atmospheric pressure. The theoretical model based on the diffusion-controlled breakdown mechanism is proposed to analyze the electrical breakdown phenomenon in this rf capacitive plasma source of the coaxial cylinders. The electron temperature at the electrical breakdown is calculated from the theoretical model, thereby evaluating the electrical breakdown voltages. The experimental data of the electrical breakdown voltage are measured with respect to the variation of the geometric parameters of plasma source, the gas temperature, and the concentration of the foreign reactive gases ͑oxygen and nitrogen͒ mixed in the helium gas. The theoretical results of the electrical breakdown voltage agree remarkably well with experimental data. This indicates that not only the electron temperature is important in determining the electrical breakdown voltage, but also the geometric variables, the gas temperature, and the scattering cross sections of molecules play significant roles.

Aging of surface properties of ultra high modulus polyethylene fibers treated with He/O2 atmospheric pressure plasma jet

“…According to the literatures [31,32], an oxygen molecule may absorb an electron to form a stable negative ion, releasing certain amount of energy. There are two main reactions involved in the electron capturing processes for oxygen: One is the two-body attachment process:…”

Atmospheric-pressure gas breakdown from 2 to 100 MHz

“…Above 20 MHz in Fig. 1͑a͒, the increase in breakdown voltage with increasing frequency for d = 1.0, 1.5, and 2.0 mm has not been reported for rf APGD [4][5][6] and low-pressure rf plasmas. [10][11][12]16 Following the same notation as that for the second critical frequency, we refer the frequency of the minimum breakdown voltage as the third critical frequency.…”

“…3 However, there are surprisingly few reports of breakdown of rf APGD, most of which are for frequencies below 50 MHz and modest reduced electric field of E / N = ͑0.1-1.0͒ ϫ 10 −19 V m 2 in an inert gas ͑e.g., helium or argon͒. [4][5][6][7] For molecular gases, breakdown studies of VHF high-pressure plasmas are equally scarce 8,9 and often limited to atmospheric air with markedly higher reduced electric field of E / N = ͑1.2-5.2͒ ϫ 10 −19 V m 2 . These limited studies suggest that breakdown voltage decreases with increasing frequency due to a diminishing role of electron wall loss.…”

Coaxial rf atmospheric pressure dielectric barrier air–helium plasma characteristics

“…Atmospheric pressure rf plasma systems consist of different varieties of electrode forms: naked electrodes [8] and electrodes covered by dielectrics [9,10] and can have different geometries. Parallel plate and concentric cylinders [11] are two simple examples. In previous investigations the electrode separations were small, typically a few mm between the electrodes.…”