Long and uniform plasma columns generated by linear field-applicators based on stripline technology

Abstract

Long plasma columns generated by high-frequency (HF) fields and extending over distances longer than the free-space wavelength of the applied electromagnetic (EM) field are of interest in various applications. A commonly used method to achieve such long plasma columns calls for the propagation of EM surface waves that use the plasma as their propagating medium. In such a case, the HF field applicator, called a wave launcher, is much shorter than the actual length of the plasma column. Long plasma columns can also be sustained by using field applicators that run along the full length of the discharge tube. Most such linear applicators rely on waveguide components. However, it is possible to use transverse electric magnetic planar-transmission-lines based on stripline technology to design efficient linear field applicators. Using such an approach, we have developed a new type of HF linear field applicator that operates on a relatively wide frequency range (typically, 200-2450 MHz). Comparison of the discharge that it generates with a surface-wave discharge (SWD) sustained under similar operating conditions shows that the discharge volume is larger than that obtained with a SWD at the same power level, hence a lower gas temperature and a plasma column more axially uniform, two valuable features for some applications. The contraction of these plasma columns is shown to occur at higher gas pressures than with SWDs. All these measurements are carried out in argon as the discharge gas.

Microplasmas: Sources, Particle Kinetics, and Biomedical Applications

“…In most designs, the plasma dimensions are much smaller than the excitation wavelength and the discharges can be regarded simply as capacitively coupled plasmas operated at GHz. Microstrip and stripline technologies, however, have also been used to generate plasmas with dimensions comparable to the RF excitation wavelength 151. Schematics of microwave microplasma sources are shown in Figure 5.…”

Spectroscopic characterization of a neon surface-wave sustained (2.45 GHz) discharge at atmospheric pressure

“…By using the values of r determined experimentally and relationship (16), the value of the coefficient k 01 of the most self-absorbed line was obtained. Finally, from Eq.…”

“…Nowadays, MIPs are being used in analytical chemistry, in spectroscopy, in the sterilization of medical instruments, for gas detoxification, in surface processing [1][2][3][4], etc. A large set of MIPs has been developed in the last two decades [1,[5][6][7][8][9][10][11][12][13][14][15][16][17]. Among them, surfacewave sustained discharges (SWDs) in dielectric tubes [1] are especially interesting because of their unique features such as high flexibility, ease of handling and their ability to be generated under broad ranges of experimental conditions (pressure, frequency, type of gas).…”

Gliding arc triggered microwave plasma arc at atmospheric pressure for coal gasification application

“…3,4 Microwave plasma torch has also been applied for diamond synthesis 5,6 . Among all research work on microwave, the microwave plasma arc with waveguide fed applicator is most common that has been applied for different applications [7][8][9][10][11][12] . The microwave plasma arc has also been applied for treatment of gasoline for hydrogen generation 13,14 In this report, the microwave plasma arc generation is emphasized using a commercial microwave source of 1kW rating.…”