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Flashover on insulator surface in the air at atmospheric pressure occurs as a sequence of several processes and leads to the formation of a plasma channel which bridges the electrode gap. The streamer-to-leader transition is a very critical stage of such a breakdown since the leader can propagate a long distance with a low increment of application voltage. The transition and the propagation process...
For more than one decade, the surface dielectric barrier discharge (SDBD) has been extensively studied in aerodynamic applications as electro-hydrodynamic (EHD) actuators [1]. The SDBD was also largely studied for air pollution treatment due to the lower discharge ignition voltage and the larger contact surface with catalyst than the volume DBD [2]. The propagation and expansion mechanism of discharge...
This study investigated the discharge uniformity in helium dielectric barrier discharge jets (DBD jets) with various operation parameters. The significant reduction of the discharge uniformity was found to be induced by various operation modes in the DBD jets, in which concentrated plasma channels with relatively high intensity are created. This may lead to non-uniform treatment if the DBD jets are...
Multipactor is a limiting factor in a many RF systems, restricting performance, efficiency, lifetime and reliability. In many situations it is possible to avoid multipactor by various suppression methods or the avoidance of specific operating points. However this cannot always be achieved. When multipactor cannot be avoided, the saturation level becomes critical. In for instance, superconducting applications,...
The homogenous discharges in helium, neon and argon begin with Townsend discharge and end at sub-normal glow discharge. The current limitation by dielectric induces the discharge end before normal glow discharge is reached. Penning ionization between the metastable atoms of the noble gases and impurities plays an important role in the formation of the homogenous discharges. It is easy to realize homogeneous...
The Diffuse Coplanar Surface Barrier Discharge (DCSBD) has shown its great potential for applications in textile industry recently1. A rather interesting synthesis of the latest technologies and a very traditional industry is currently being developed in cooperation of our physics department and TONAK - a company with more than 200 years tradition in the hat making from natural felt. This is also...
As one of the critical elements of fast linear transformer driver(FLTD), gas switch influences the output characteristics, stability and reliability of FLTD. In this paper, a new multichannel gas spark closing switch has been designed for LTD. The trigger electrode is mainly constituted of eight pin electrodes, each pin electrode is surrounded by cylindrical insulation sleeve to produce surface flashover,...
Development of high power microwave (HPM) distributed discharge limiters relies critically on minimizing the delay time between HPM incidence and diffuse plasma creation. We present a series of pulsed plasma experiments conducted in neon, argon, and a 9∶1 mixture of the two gases from 50–760 torr. Breakdown is achieved by illuminating a gas cell with a train of ∼25kW, ∼2 kV/cm, 800ns-long pulses at...
Microwave discharges sustained by traveling electromagnetic waves have been attracting much attentions among others, because their broad range of operating conditions. Well known configurations are the cylindrical plasma columns generated by surfatron or surfaguide launchers. This study, however, is devoted the coaxial structure in which the plasma is created by a rod antenna positioned in the center...
The initiation of the explosive electron emission pulses - ectons being responsible for the ignition and burning of a vacuum discharge, in particular, - unipolar arcs1. The latter being a common feature of intense plasma-surface interactions in fusion devices. A fusion devices first wall with a strongly non-uniform surface, as well as an intense power load onto the surface in the edge localized modes...
Flexible displays, flexible paper related electronic products are important development tendency in micro-electronics industry. At present, increase the adhesive strength between flexible organic substrates and ITO film quickly and efficiently and ensure the reliability of the adhesive between them is a burning question. By pulse modulate technology, we investigated the mechanism and effects of secondary...
Nonthermal plasma proved to be a more economical and ecological replacement of conventional technologies for various applications such as sterilization, NOx removal or surface treatment of polymers [ 1 ] . Microplasma has advantages over other types of nonthermal plasma due to its generation at low discharge voltage and atmospheric pressure.
Effect of Joule heat generation in the cathode body is investigated in the framework of the model of nonlinear surface heating, which is a widely used tool of simulation of plasma-cathode interaction in high-pressure arc discharges1. Special attention is paid to investigation of thermal balance of the cathode and the near-cathode plasma layer. Calculation results are reported for tungsten cathodes...
A comprehensive understanding of interaction between plasmas and soft-materials is essential for advanced plasma processing technology. Simultaneous measurements of signals arisen form both the gas-phase species and the surface dangling bonds, and kinetics analysis of radical formation was performed using in situ real-time electron spin resonance (ESR)[1]. Chemical reactions under plasma are very...
In general non-thermal plasma generates three main types of bio-active agents: UV radiation, charged particles and neutral species like radicals and metastables. A role of each agent in bio-inactivation of microorganisms still remains as the subject for discussion. To simplify situation, we used pin-to-plane positive and negative DC coronas in ambient air as a source for generation of bio-active agents...
The treatment of liquid with a surface dielectric barrier discharge (DBD) under atmospheric pressure in air results in pH decrease and generation of nitrate (NO3−), nitrite (NO2−) and hydrogen peroxide (H2O2) in water. Even, after plasma treatment antimicrobial effects on suspended microorganisms were investigated [1] [2].
In this work, the preparation of an antibacterial polyethylene film for using in food packaging was studied. Silver nanoparticles were used, because of their antibacterial property. For this purpose, a colloidal solution of silver nanoparticles was synthesized by chemical reduction of silver slat using fructose as a reducing agent. The absorption spectra of silver nanoparticles prepared by the proposed...
The use atmospheric plasma sources for applications in the aerodynamical and aeromotive sector is relatively new1. The research focused mainly on the aerodynamics performances and to a much lesser extent to the plasma state. Indeed diagnostics of atmospheric pressure plasmas are very demanding because of the short temporal and the small spatial scales involved in the plasma state and in the different...
The low pressure mercury lamp is dominating the lighting market for decades. In these lamps the electrode loss is one the dominant factors that limit the efficacy of the lamp. Thus by removing the electrodes and sustaining the discharge with surface waves, the efficacy, which the lamp ideally delivers, can be obtained. In addition, with electrodes associated failure mechanism like the loss of emission...
Plasma display with large cell size is gaining attention for the application of large outdoor public and transparent display. In the previous work, it has been shown that the efficacy of opposite discharge reaches to 18 lm/W, while that of surface discharge is about 5 lm/W.[1,2] As a follow-up research, discharge properties of PDP cell having diagonally opposite electrode have been investigated in...
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