Optical and electrical characterization of pulse-modulated argon atmospheric-pressure inductively coupled microplasma jets

Abstract

The critical parameters determining the generation of the pulse-modulated argon atmospheric-pressure inductively coupled plasma (AP-ICP) microjet were studied by varying the power, P, pulse-modulation frequency, f, and duty ratio, DR. The temporal changes in the net output power, Pnet, monitored between the very high frequency power supply and matching network by an rf sampler, and ArI 4s′[1/2]1O–4p′[1/2]0 emission from the antenna were measured to elucidate the behavior of this plasma. The AP-ICP microjet, which produces high-density (0.9–1.1×1015 cm−3) nonequilibrium plasma, consists of an alumina discharge tube with the inner diameter of 0.8 mm. The generation diagram of the pulse-modulated plasma was created by having f as the horizontal axis and DR as the vertical axis while varying P up to 50 W. At f≤10 kHz, the plasma was generated at above the linear lines of f and DR, which indicated the existence of the critical power-off period of approximately 80 μs. At f>10 kHz, the pulse-modulated plasma was produced above constant DR and almost independent of f. The time-averaged power, P¯, which is the product of P and DR, had to be more than 8–10 W to sustain the pulse-modulated plasma. From the measurement of the temporal changes in the net power and ArI emission, the dynamic behavior of the pulse-modulated plasma was revealed as follows. The prebreakdown period was present for ∼5 μs after the power was turned on. Once the plasma was generated, the impedance was changed and the reflected power gradually decreased. A strong emission peak was observed immediately after the breakdown, followed by the gradual increase up to the steady state. Finally, the intense afterpeak was observed at 0.8 μs after the power was turned off.

Correlated mode analysis of a microwave driven ICP source

“…By downsizing the plasma reactor, the surface to volume ratio increases making the ICP mode still more efficient. There are many variants of inductive coupling to a plasma [7][8][9][10][11][12][13][14][15][16]. To our knowledge none of these papers makes an analysis of the E-H mode transition and of the efficiency of the power transferred to the plasma.…”

The double coupled microwave resonance probes and application for diagnosing atmospheric pressure plasma jet

“…Atmospheric pressure glow discharges (APGDs) [1][2][3][4] have attracted great interest because of their enormous advantages such as no expensive vacuum systems, the absence of heat damage due to the operation in the nonthermal glow and the capability to produce reactive species, charged particles, and UV radiation. In recent years, various types of APGDs have been developed to apply in material processing [5], biomedical processing [6,7], nanotechnology [8], conventional etching [9], and deposition [10].…”

Theoretical Electromagnetic Field Calculation of a Floating Metal Wire for Inductively Coupled Micro Plasma Using a Spiral Coil

“…The external power supply (for example, a high voltage DC or AC power supply) for generating a thermal electron or dielectric barrier discharge is used. [19][20][21][22] Ito et al reported regarding using tungsten wire, which is usually connected to ground; for generating thermal electrons, a pulse of about a 15 kV voltage is applied to 0.5 s. 23) This means there is a necessity for a supply of additional power and additional wiring. The miniaturization of the plasma source is disturbed, making the total system complicated with the additional power source.…”