2 edition of interaction of microwaves with the cathode fall and negative glow in a glow discharge. found in the catalog.
interaction of microwaves with the cathode fall and negative glow in a glow discharge.
P. J. W. Severin
|Series||Philips research reports supplements -- 1965; 2|
As the current passed through a gas discharge tube is increased beyond the levels at which normal glow discharge takes place, such normal gas discharge being characterized by a negative resistance characteristic leading to decreasing potential between the cathode and anode electrodes of the tube, a region of abnormal glow discharge is entered. William Robert Grove who reported the formation of films near the cathode of a (pulsed!) glow discharge in  (Fig. 2). Grove, as many others, used pulsed high the cathode fall voltage in the cathode sheath, which much later was used as the physical book on energetic ion-solid interaction, Ziegler, Biersack and Littmark.
A cold cathode vacuum discharge tube is used in a circuit for generating pulsed autoelectronic emissions which are particularly intense and frequent in the abnormal glow discharge region, and involve much lower current densities than predicted by the Fowler-Nordheim vacuum arc discharge region law. The discharge tube is characterized by a large electrode area at least of the cathode, . An additional electron source known as a neutralizer is used to neutralize the positive ion beam with an equal amount of negative electron current. At the U-M Plasma Science and Technology Laboratory, a waveguide microwave plasma cathode is being studied as a proof of concept for a long-lived alternative to emitter-based electron sources.
The discharge of interest is a pulsed abnormal glow discharge, but this pulsation is triggered autogenously at low applied field by a spontaneous electronic emission under cold-cathode conditions (). Furthermore, this emission-triggered pulsed abnormal glow discharge is repetitively cycled in a self-generating or endogenous action, thus. Microwave interaction with materials can be predicted if dielectric properties (relative dielectric constant ε’ and relative dielectric loss factor ε”) are known. The loss tangent tanδ =ε ” /ε’ is an indicator of the ability of the material to convert absorbed energy into heat. A good absorber has tanδ≥ while those with.
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Add tags for "The interaction of microwaves with the cathode fall and negative glow in a glow discharge,". Be the first. The composite discharge tube The practical realization of the MW-coupled hollow cathode lamp was achieved by modifying a commercially available Grimm's glow discharge device as TABLE I.
Cathodic materials and solutions subjected to discharge in the MW-coupled hollow cathode lamp Cathodic Material Solution Aluminium Zinc Copper Nitrate Cited by: A glow discharge is a plasma formed by the passage of electric current through a gas.
It is often created by applying a voltage between two electrodes in a glass tube containing a low-pressure gas. When the voltage exceeds a value called the striking voltage, the gas ionization becomes self-sustaining, and the tube glows with a colored light.
The color depends on the gas used. Commonly, cathode fall region is very important for the behavior of glow discharge. In cathode fall region, there are plenty of space charges that distort the electric field, and thus, the secondary electron emission process is maintained.
The stability of cathode fall region is a precondition for stable glow discharge. The assumption that the position of the negative glow peak coincides with the edge of cathode fall layer was verified based on a two-dimensional model, and the cathode fall thicknesses, d c, were.
The volume of the experimental vessel is enlightened by a negative glow, which is an essential part of a discharge in the hollow cathode regime. Decrease of the working gas pressure from 10 to 1 Pa visibly improves the discharge uniformity: the glow expands in the whole chamber, as the mean free paths of the fast secondary electrons become longer.
With more ions produced in the discharge, a cathode fall region tends to be formed. Hence, the discharge transits to the glow mode with decreasing T r. With further decreasing T r, the discharge turns stronger and the current density becomes higher, which leads to the transition from the normal glow mode to the abnormal glow one.
The blue light near the opposite electrode (the cathode) is nitrogen first negative emission, and is caused by the impact of electrons on N 2 + ions. This emission was first identified in sprites by Russ Armstrong of Mission Research, Matt Heavner of Los Alamos. Another DC glow discharge was generated between a thin cylindrical anode and a flat cathode with helium, argon, hydrogen, nitrogen and air used as working gas respectively 9.
supply. A dc voltage applied between the anode and cathode pro- duces a negative glow discharge, the behavior of which is quali- tatively similar to that of a brush cathode discharge (ref. 5); that is, the plasma is beam-generated and the elec ron density is sufficiently high (i.e., on the order of 10l2 e/cm).
The length of the cathode sheath is ≈ cm, while the inner, negative glow part of the discharge has a diameter of about cm. Inside the negative glow we do not find a plasma potential. The discharge is restricted to the cathode fall and negative glow, with the negative glow serving as a virtual anode.
The plasma in the negative glow region provides a radial current path to the ring-shaped metal anode. These approximations are less suited to modeling boundary regions such as the cathode fall and negative glow regions of dc discharges.
The breakdown of fluid approximations is due to the proximity of the boundary and the resulting large gradients in electric field, electron density, average electron velocity, and average electron energy.
current glow discharge of lower and upper cathode plate, whose electron currents are both radially scattered into the anodic glow discharge region on grounds of the Townsend ionization avalanches; the acceleration of ions from theunder-dense anodic plasma zone towards the central plasma, and the continuation of the static radial ion current by.
Hydrogen-Surface Interactions. Hopman. Pages Plasma Assisted Thin Film Production WC, a-C:H and Diamond Films Spectroscopic Diagnostics in the Cathode Fall and Negative Glow of a Nitrogen Glow Discharge. Jacques Jolly. Pages Electron Kinetics in RF Discharges. Toshiaki Makabe. The book tries to reproduce these.
Read this book on IOPscience; Recommend to Library × Close. Paperback $ Ebook i $ Add to Cart Introduction to the Kinetics of Glow Discharges Chengxun Yuan, Professor Anatoly Kudryavtsev. Current dry etching systems use glow discharges with gas pressures ranging typically from to Pa.
Electrical power supply is by ac only, with frequencies of 50 kHz and up. High-frequency excitation is applied as it takes out the necessity to draw direct current through the system. The purpose of the NATO ARW was to develop applications, and an improved understanding of the physics for high current emission and conduction observed in hollow cathode-hollow anode switches including the pseudo spark and BLT.
New applications include highly emissive cathodes for microwave. rapidly and transition from a “glow discharge” to what is referred to as an “arc discharge”. The arc is formed when heating of the cathode results in ejection of electrons through thermionic emission.
The lamps require a high starting voltage to initially heat the electrodes (Phillips ). The Negative Corona The Absence of Positive Corona Glow Discharges General Features of the Glow Discharge Crookes Dark Space and the Cathode Fall of Potential The Negative Glow The Positive Column The Positive Column in a Longitudinal Magnetic Field The Anode Fall Steady-State Microwave Discharges Comparison of Steady-State and Breakdown Fields.
A duoplasmatron is a type of glow discharge ion source that consists of a cathode (hot cathode or cold cathode) that produces a plasma that is used to ionize a gas.
Duoplasmatrons can produce positive or negative ions. Duoplasmatrons are used for secondary ion mass spectrometry., ion beam etching, and high-energy physics. Benesch, W. and Li, E. Line shapes of atomic hydrogen in hollow-cathode discharges.
Optic Lett. 9, – Brauner, T. Particle .Hollow cathode discharges are glow discharges with the cathode fall and negative glow confined in a cavity in the cathode. For the discharge to develop, the cathode hole dimensions must be on the order of the mean free path.
By reducing the cathode hole dimensions it .