Formation Of Volume Discharge Research Articles

Kinetic Model of Volume Discharge Formation on the Left Branch of a Paschen Curve with Cathode Initiation of a Breakdown

Physical features of the formation of a low-pressure volume discharge in a flat-pack diode are demonstrated using a kinetic description of the electron and ion plasma subsystems. Modeling allows all details of this process to be followed, including the evolution of the distribution functions of electrons and ions over energies at all stages of breakdown development. The mechanism behind the formation of the flow of ions to the anode in the nonstationary phase of breakdown is revealed.

A dot-line square super-lattice pattern with surface discharge in dielectric barrier discharge

We report a dot-line square super-lattice pattern with surface discharge (DLSSPSD) in a dielectric barrier discharge system and show for the first time that the surface discharge can promote the formation of volume discharge (VD). The pattern consists of three different discharge morphologies, namely, bright spots, dim spots, and bright lines. The spatiotemporal dynamics of the DLSSPSD are studied using an intensified charge-coupled device camera, a photomultiplier, and a high-speed video camera. The results show that the VD located at the dim spots and bright lines is generated on both the rising and falling edges of the voltage. It is found that the high surface charge density transferred by the surface discharge of the bright spots promotes the formation of VD at the dim spots and bright lines.

Peculiarities of the ionized fronts formation and development in pre-ionized gas

We present the results of the investigation of the initial stage of volume discharge formation in helium of atmospheric pressure. The investigation of the non-locality of energy distribution influence on the ionization wave parameters in the front area is carried out on the basis of a two-dimensional axial-symmetry drift-diffusion model. The results of numerical calculations are in a satisfactory agreement with the experimental data.

High-power subnanosecond beams of runaway electrons and volume discharge formation in gases at atmospheric pressure

A non-local criterion for runaway electrons generation is proposed, which is a universal two-valued dependence of the critical voltage U cr on pd for a certain gas (where p is the pressure and d is the interelectrode distance). This dependence subdivides the (U, pd) plane into an area of efficient electron multiplication and an area in which electrons leave the gas gap without multiplication. Electron beams of subnanosecond pulse duration and an amplitude of hundreds of amperes are generated at atmospheric pressure in various gases. A volume nanosecond discharge with a high specific excitation power was realized without the pre-ionization of the discharge gap by using an additional external source. The role of the electron avalanches propagating from the cathode to the anode in a dense gas was considered.

The role of fast electrons in the formation of a pulsed volume discharge at elevated gas pressures

A volume electric gas discharge was obtained using a pulsed inhomogeneous electric field without a preionization source in various gases (nitrogen, air, helium, neon, argon, krypton) at elevated pressures. In air at atmospheric pressure and nanosecond voltage pulses, the specific energy deposited in the gas amounted up to ∼1 J/cm3. The mechanism of the volume discharge formation is related to the appearance of fast (keV-energy) electrons emitted from plasma formations at the cathode. Fast electrons provide for the effective preionization of the gas in the interelectrode space and favor the formation of volume discharge. Under these conditions, the maximum voltage drop across the discharge gap is achieved in the quasi-stationary stage of discharge.

Conditions of self-sustained volume discharge formation and their influence on its glow stability

Abstract Influence of the gas mixture pressure, geometrical dimensions of active volume and the density of initial electrons on stability of a self-sustained volume discharge are discussed. These parameters affect on the stage of the discharge formation, which results in the appearance of a cathode layer. The structure of the latter (the distribution of cathode spots and channels over the cathode surface) depends strongly on the self-sustained discharge. Experimental observations are in a good agreement with the data obtained from the analysis of the cathode channels and spots distribution over the cathode surface.

Formation of a volume discharge for the pumping of CO2lasers

An investigation was made of the characteristics of the formation of a self-sustained volume discharge for the pumping of CO2 lasers, which involved a preliminary filling of a discharge gap by an electron flux from an auxiliary-discharge plasma. It was found that this method was suitable for large interelectrode gaps. It was found that distortion of the electric field in the gap by the space charge of the electron flux played an important role in the formation of the discharge. It was found that the electrodes could be profiled dynamically during propagation of an electron flux through the discharge gap and a self-sustained volume discharge could form in systems with a strongly inhomogeneous initial distribution of the electric field between the electrodes.

Mechanism of formation of a volume discharge initiated by a barrier discharge distributed on the surface of a cathode

A study was made of the mechanisms of formation of a self-sustained volume discharge in CO2–N2–He gas mixtures initiated by an auxiliary barrier discharge distributed on the surface of a cathode. The volume discharge was initiated when the discharge gap was filled by an electron flux formed from the barrier discharge plasma in the course of a smooth rise of the voltage across the electrodes. Measurements were made of the small-signal gain confirming the model of formation of a self-sustained volume discharge and demonstrating that a discharge of this kind could be used to amplify nanosecond light pulses.