Diagnostics of the atmospheric-pressure plasma parameters using the method of near-field microwave sounding

Abstract

A method of resonant near field microwave probing is developed for contactless diagnostics of a high pressure plasma. The efficiency of this method in measuring the parameters of the plasma of an rf capac itive discharge in argon under atmospheric pressure is demonstrated. The experimental results are compared with the data obtained using the independent method, the microwave radiation "cutoff," and with theoretical estimates.

Application Of Rf (13.56 MHz) Arc Discharge For Plasma Chemical Conversion Of Volatile Fluorides

“…R is the active resistance of the plasma, C = S/(4πL) is the capacity of the space between the DEL filled with plasma, where S is the characteristic cross-sectional area of the plasma arc, L is the characteristic dimension of the plasma, = −ω pe 2 /ν 2 en is the dielectric constant of the plasma), R1 is the active resistance resulting in the heating of the electrodes, connected with the flow of thermoelectrons and electrons that have passed from the plasma through the DEL to the electrodes, C1 = S1/(4πd) is the capacity of the DEL, where S1 is the area of the electrodes, d = 3r D (the radius of the Debye) is the characteristic longitudinal size of DEL. The value of R is determined by the formula R = L/σS, where L is the characteristic dimension of the plasma, S is the characteristic crosssectional area of the plasma arc, and σ = ω pe 2 /4πν en is the conductivity of the plasma [12]. The resistance and impedances of this circuit are calculated according to this formula and are equal to R = 6 Ω, Z C = 10 Ω, Z C1 = 400 Ω, where Z C = 1/iωC is the impedance capacitance C. Since R is comparable with Z C , there are two components of the electric current in the plasma: the conduction current and the bias current.…”

The simulation of terahertz waves transmission in the arc plasma

“…The most frequently used techniques for determining the electron density are optical diagnostics, including Thomson scattering method, continuum radiation, atomic line Stark broadening, and so on [12,14,15]. Microwave diagnostic [16][17][18][19][20][21] is an effective method to measure various plasmas with plasma density below 10 13 cm −3 , however, it is invalid to measure the plasma of higher density due to the limited frequency of microwave [22].…”

Subsurface diagnostics of quasi-one-dimensional inhomogeneities using the method of near-field microwave sounding

“…The method of resonance near-field sounding [1][2][3] is used successfully to study electrodynamic properties of various substances in the microwave range. Depending on the operating frequency, either oscillatory circuits with lumped parameters or distributed resonance systems can be used as measurement sensors.…”