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Microplasma arrays are being investigated to manipulate the propagation of electromagnetic waves [1]. Such applications require control of plasma properties over large dynamic ranges across a large area, resulting in control of their absorption, dielectric and metamaterial properties. These microplasma arrays often operate at intermediate pressures of 10s to 100s of Torr, motivated by a tradeoff between...
When the contacts of a circuit breaker are opened just before the current zero, the gap between the contacts after the current interruption will still be very short. Therefore, it cannot withstand the recovery voltage across the contacts after the interruption. In such a case, the multiple re-ignitions likely take place. Many investigators had tried to clarify this phenomenon, and many reports have...
A sheath recovery process dominants the initial stage of a dielectric recovery process after interrupting a vacuum arc current. The objective of this paper is to model a post-arc sheath recovery process by using PIC-MCC method. Second electrons, external circuit, and fundamental collisions between particles were taken into considerate in the model. The result shows that the amplitude of post-arc current...
The results of experiments on the reproducible generation of electron beams in a vacuum diode supplied by a high-voltage pulse with amplitude of a −300 kV and duration of −600 ns are presented. A cathode based on carbon-epoxy capillary structure was used for generation of electron beams with current density of up to 600 A/cm2 and a satisfactorily uniform cross-sectional distribution of current density...
The high-current (up to 20 kA) electron gun with plasma anode based on combined discharge which matches high-current Penning discharge and vacuum sparks has been studied. It is shown that suggested method for creation of plasma anode improves the uniformity of beam energy density via its cross section. The improvement of the beam uniformity is achieved due to increasing of the anode plasma density...
Langmuir-probe-based diagnostics of sheath dynamics in the conditions of current zero followed by TRV escalation were performed for both freely burning vacuum arc with CuCr25 electrodes as well as arc stabilized by axial magnetic field of 7 mT/kA. Tests were done using synthetic circuit and experimental set-up simulating vacuum circuit breaker under short-current operation. The sheath boundary in...
A considerable advance has been made recently in the development of small-sized picosecond pulsed power supplies [1]. Advantage was taken of these power supplies and techniques for diagnosing fast processes to perform a detailed experimental study of the runaway electron beams (REBs) generated during breakdowns in atmospheric-pressure gas-filled diodes [2–4]. The basic features of these REBs, such...
Pseudospark discharge is a specific type of gas discharge, which operates on the left-hand side of the hollow cathode analogy to the Paschen curve with axially symmetric parallel electrodes and central holes on the electrodes. Plasma simulation is carried out to study the initiation phase of pseudospark discharges. The pre-breakdown and breakdown phases of a pseudospark discharge are investigated...
The Post Arc (PA) phase of Vacuum Interrupters (Vis) and the effects of dominant physical parameters of vacuum arc investigated in this paper. 2-D movement of PA plasma in the presence of Transient Recovery Voltage (TRV) is simulated in a proper Finite Element Method (FEM). The residual plasma at Current Zero (CZ) crossing is assumed in the inter-electrode space. Due to simplify the problem, a cylindrical...
A 2D model of sheath expansion and plasma decay for transient recovery voltages has been developed in order to improve understanding of the physical phenomena related to the post-arc phase. This new model considers charged and neutral particles produced during the arcing period, electrode evaporation and also the collisions between charged species and metal vapor atoms. New 2D simulation results are...
Ignition of explosive electron emission centers (ectons) is a great problem if operating voltages are rather low and vacuum conditions are clean. However, dense enough plasma adjoining directly to the cathode surface promotes new ectons to be ignited. The idea of the present work is an attempt of using laser ablation plasma to stimulate ignition of ectons. For tests, a gap formed by the ring anode...
Summary form only given. An Inertial Electro-static Confinement Fusion (IECF) device is one of the candidates among the neutron sources, and it is possible to produce the neutrons by a compact device of simple configuration. The IECF is a concept for electrostatically confining high-energy fuel ions in a spherical potential well. It consists of two grid electrodes, radii are different and centers...
Summary form only given. In order to extend the capability of the Hybrid Plasma Equipment Model (HPEM)1 simulation code to increasingly lower operating pressure conditions, the direct simulation Monte Carlo (DSMC)2 method is used to improve the modeling of the heavy particle species in a hollow cathode magnetron (HCM) plasma reactor, a device used to implement the Ionized Metal Physical Vapor Deposition...
Summary form only given. Communications blackout, which is experienced by spacecraft re-entering the atmosphere at hypersonic velocities, is caused by the formation of a dense plasma envelope produced by shock heating. Communication signals at frequencies below the plasma cutoff frequency cannot propagate through this layer. Methods suggested for mitigating blackout have included aerodynamic shaping,...
Summary form only given. Breakdown of the gaps with a non-uniform electric field filled with nitrogen and air as well as with other gases under high-voltage nanosecond pulses was investigated. It is shown that conditions of obtaining a diffuse discharge without a source of additional ionization are extended at the voltage pulse duration decreasing. A volume discharge is formed due to the gap preionization...
A dispersion equation is derived for three-dimensional waves in a warm constant-density cylindrical electron beam confined in a uniform magnetic field. The transverse temperature decreases with radius, from a maximum on axis to zero at the beam edge in a manner that results in rigid-rotor equilibria. The model introduces both an axial thermal parameter TAXN and a transverse thermal parameter TEQ.
Summary form only given. The rod-pinch diode is a co-axial relativistic electron-beam-driven diode, where the cathode is a hollow disk and the anode a rod protruding through the cathode. The diode operates at currents in excess of the critical current such that electrons emitted from the cathode are magnetically insulated from crossing the A-K gap and are forced to attach at the tip of the anode rod,...
Trench gate MOS controlled devices are more desirable in power modules because their reduced Vce(sat) enables increased output power density. However with increased drift region thickness with voltage rating, there is significant increase in conduction loss in Trench gate IGBT (T-IGBT) due to low plasma density from inherent pnp transistor action. On the other hand a well-designed trench gate MOS-controlled...
Summary form only given: Electric propulsion (EP) systems and plasma contactors usually rely on thermionic emitters as primary electron sources. The most frequently used device is the hollow cathode assembly (HCA). The HCA employs a barium-impregnated tungsten insert to generate a plasma within an orifice, from which electron current is extracted. While HCAs are efficient electron sources, the presence...
The problem of a reliable electron source is one of a crucial issue in efficient operation of relativistic microwave tubes. In this report we present results of comparison of experimental research of the relativistic magnetron operation with commonly used explosive emission plasma cathode and novel ferroelectric plasma source cathode. The latter allows one to form the plasma prior to the accelerating...
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