Electron density measurements in an atmospheric pressure argon discharge by means of plasma radiation

Abstract

A method is developed for measuring the electron density in argon during atmospheric pressure dielectric barrier discharge. The oscillating electromagnetic signal is detected by an antenna at a distance from the plasma source. The electron density is then calculated from the ion oscillation frequency. The results show that the electron density in the plasma after the turnoff of the discharge channel is 2.55×1019 m−3 with an applied voltage of 2.73 kV, and it decays almost exponentially down to 1.00×1019 m−3 over 49.2 ns. The electron density is found to increase linearly with increasing voltage.

Helium corona-assisted air discharge

“…2(c)), which may result from the plasma oscillation following the steep rise of the discharge current. 12 The spikes correspond to the streamer process and propagate quite fast. In contrast, the broad pulses at low voltages are related to the corona process, where the discharge current propagates via ion diffusion, thus being weak and slow.…”

Diagnosis of ion velocity distribution from pin to plate geometry in atmospheric argon dielectric barrier discharge

“…5(a). Secondly, the capacitance of a concentric cylinder discharge device we used before is about 4.082 nF; 12 it is much larger than that of 1.180 pF used in this experiment. However, results show that the oscillation frequencies in the order of 10 8 Hz are similar 12 in radiation signals from the two different discharge devices if they are working at same discharge mode.…”

“…Thirdly, in the concentric cylinder discharge device, the radiation signal from plasma jet, where the ion density is different from that in filament discharge region, is measured by shielding the radiation signals from the filament discharge region using a steel grid. The average oscillation frequency of radiation signal is in the order of 3:4 Â 10 7 Hz, which is lower 3.56 times than that radiated from filament discharge region, 12 shown in Fig. 4.…”

“…11 In 2009, we developed the plasma radiation method based on the plasma oscillation probe to measure ion density by receiving radiation from within the plasma. 12 The most significant advantage of this diagnostic method is that thermal equilibrium condition is not necessary because the radiation signals received by the antenna originate directly from the linear superimposition of charged particle radiations. In this letter, we adopt a fast Fourier transform to calculate ion velocity distribution in onedimensional space using a dipole model.…”

Neutral gas temperature maps of the pin-to-plate argon micro discharge into the ambient air

“…They can be used as anatytical tools, photonic devices, in the surface treatment of vulnerable materials, bacterial inactivation processes, surface modification, chemical vapor deposition, plasma etching on films [8][9][10][11][12][13] . Characteristics of micro plasmas, such as neutral gas temperature, electron temperature, electron density, ion density, electric field and so on, play an important role in physical and chemical processes [14][15][16] . There are many studies concerning the relationship between the bulk gas temperature and control parameters, for example, discharge current and gas flux, where the gas temperature is estimated using radiative transitions of diatomic molecules [17][18][19][20][21][22] .…”