Electric discharge

About: Electric discharge is a research topic. Over the lifetime, 13085 publications have been published within this topic receiving 123096 citations. The topic is also known as: discharge.

Theoretical models of the electrical discharge machining process. II. The anode erosion model

Abstract: As a second in a series of theoretical models for the electrical discharge machining (EDM) process, an erosion model for the anode material is presented As with our point heat‐source model in the previous article, the present model also accepts power rather than temperature as the boundary condition at the plasma/anode interface A constant fraction of the total power supplied to the gap is transferred to the anode The power supplied is assumed to produce a Gaussian‐distributed heat flux on the surface of the anode material Furthermore, the area upon which the flux is incident is assumed to grow with time The model is capable of showing, via the determined migrating melt fronts, the rapid melting of the anodic material as well as the subsequent resolidification of the material foation from plasma dynamics modeling could improve substantially our results

Plasma potentials of 13.56-MHz rf argon glow discharges in a planar system

Abstract: The plasma potential of 13.56‐MHz low‐pressure argon glow discharges has been measured for various modes of applying the rf power in a geometrically asymmetric planar system. The plasma potential is determined from the energy distribution of positive ions incident on the grounded electrode. The voltages on the excitation electrode (target electrode) are carefully measured and the capacitive sheath approximation is used to relate these measured voltages to the measured plasma potential. This approximation is successful in most of the situations encountered in this low‐pressure (20 mTorr) relatively low‐power density regime. The effects of superimposing dc voltages on the excitation electrode are discussed.

Preliminary Investigation of Prebreakdown Phenomena and Chemical Reactions Using a Pulsed High-Voltage Discharge in Water

Abstract: Prebreakdown phenomena in water were investigated for point-plane geometries using high-voltage pulses. Spot discharges, filamentary magenta streamers, isolated microdischarges, and microbubbles were observed and photographed. Emission spectra were obtained using a prism spectrograph. Maximum streamer lengths were determined as a function of applied voltage, pulsewidth (decay constant), and water conductivity. The bubbling of gas through the underwater discharge resulted in the disintegration of the gas bubbles, and also caused gas-phase discharges to occur near the nozzle electrode. The production of 0 3 , accomplished by bubbling O 2 gas through a discharge in deionized water, was investigated using a colorimetric indigo dye test that measured the concentration of 0 3 in the water. Chemical reactions occurring when 0 2 or N 2 gas was bubbled through a discharge in an anthraquinone dye solution were studied by photometrically measuring the decolorization of the dye.

Ozone Generation from Oxygen and Air: Discharge Physics and Reaction Mechanisms

Abstract: Industrial ozone generation uses a special high pressure, low temperature electrical discharge which is referred to as the dielectric barrier discharge or silent discharge. The filamentary structure of this discharge and the properties of individual microdischarges are discussed. The main reaction paths for the excited atomic and molecular species in oxygen and air are identified. Possible approaches to obtain high power densities, high ozone generating efficiencies or high ozone concentrations are discussed.

A Continuum Model of DC and RF Discharges

Abstract: A continuum model of direct current (dc) and 13.56-MHz radio-frequency (RF) discharges in a parallel-plate configuration is presented. The model consists of equations for electron and ion continuity, Poisson's equation for the self-consistent electric field, and an equation for electron energy. The equations are solved for a single set of conditions and a comparison is made between the structure of a dc and a 13.56-MHz RF discharge. One of the major structural differences is the emergence, under RF conditions, of large electron conduction currents in the quasi-neutral region. This results in substantially higher electron heating in the quasi-neutral region and a consequent shift in the peak ionization rate from the cathode sheath to the quasineutral region. In addition, the RF solutions suggest that equivalent circuit models and ambipolar diffusion models are promising ways to simplify predictions of discharge physics. The ultimate goal of this work is to provide an adequate description of the discharge physics so that discharge chemistry can be understood. The latter is essential in predicting the behavior of plasma film etching and deposition reactors used extensively in electronics materials processing.