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Tuesday, May 5, 2020 | History

3 edition of A study of pulse surface flashover in a vacuum found in the catalog.

A study of pulse surface flashover in a vacuum

A study of pulse surface flashover in a vacuum

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  • 27 Currently reading

Published by Dept. of Electrical and Computer Engineering, College of Engineering, Old Dominion University in Norfolk, Va .
Written in

  • Vacuum technology.,
  • Ultrahigh vacuum.

  • Edition Notes

    Statementby Vishnukumar K. Lakdawala.
    SeriesNASA-CR -- 180291., NASA contractor report -- NASA CR-180291.
    ContributionsUnited States. National Aeronautics and Space Administration.
    The Physical Object
    Pagination1 v.
    ID Numbers
    Open LibraryOL15277219M

    understanding and calculation of vacuum forces. Three years ago, we did numerical compu-tations to evaluate the vacuum forces in all geometric con figurations of a rectangular cavity [J. Maclay, ”An analysis of vacuum fluctuation energy and Casimir forces in conductive rec-tangular cavities,” Phys. Rev. A., 61, ()].File Size: 4MB. Optical spectroscopy studies of surface breakdown of polycrystalline diamond thin films in vacuum p. Controlling the HV holdoff performance of alumina insulators in vacuum p. Flashover triggered by charge detrapping at dielectric-vacuum interface p. A laboratory study of leakage current and surface conductivity of ice samples p.

    While surface flashover in the presence of a vacuum has been studied in some detail, the mechanisms associated with flashover in an atmospheric environment need further investigation. For an aircraft based high power microwave system, atmospheric pressures ranging from torr (sea level) to 90 torr (50, ft.) are of principal concern.   High-power microwave (HPM) has broad applications in scientific research, civil and military community. HPM has the character of peak power of tens of Giga-Watt and the pulse width from tens of to hundreds of nanosecond. The intense electromagnetic breakdowns in the HPM generation, transmission and radiation systems, seriously limit the HPM systematic power capacity, and become Author: Chao Chang.

    Abstract: There is a growing interest in the physics of surface flashover between the interface of atmosphere and vacuum in some high-power systems. More specifically, the quantitative role of vacuum ultraviolet (VUV) radiation for the photoionization leading to a streamer development during the initial stages of a breakdown is unknown. Dielectric charging phenomenon, caused by the interaction effect between space environment and spacecraft material, has a severe threat to the normal operation of spacecraft. Especially, the problem becomes more serious with the improvement of spacecraft operation voltage. An overview of dielectric charging research status, exsiting problems and prospect are by: 3.

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A study of pulse surface flashover in a vacuum Download PDF EPUB FB2

A study of pulse surface flashover in a vacuum. [Vishnukumar K Lakdawala; United States. National Aeronautics and Space Administration.] based on reference standards. However, formatting rules can vary widely between applications and fields of interest or study.

The specific requirements or preferences of your reviewing publisher, classroom. Vacuum Surface Flashover: Experiments and Simulations Article (PDF Available) in IEEE Transactions on Dielectrics and Electrical Insulation 21(5) October with Reads.

@article{osti_, title = {Surface flashover of insulators}, author = {Miller, H C}, abstractNote = {This paper reviews surface flashover (i.e., voltage breakdown along the surfaces of insulators), primarily in vacuum, although some comments are made about surface/flashover in high pressure gases.

Theories and models relating to surface flashover are discussed, along with pertinent. The surface charges on alumina in vacuum after applying a negative pulse voltage (/4 μs) were measured, as well as flashover performances of the materials in vacuum.

The flashover studies were conducted using 20 ns (rise time)/ μm (half-height width time) pulse under 5 × Pa vacuum. The surface flashover properties of micro TiO 2 and Al 2 O 3 3H 2 O/epoxy composites were presented.

In addition, their dielectric spectrum and thermally stimulated depolarization current (TSDC) were measured. In this study, the influence of nanosecond pulse front steepness on flashover process in vacuum is investigated.

Firstly, flashover experiments with nanosecond pulses are conducted. Nanosecond pulses with different front steepness are generated and used to trigger flashovers on sample by: 1.

To study the effect of a large component of normal electric stress on surface flashover in vacuum, a high voltage electrode and its opposite one were mounted on a polycarbonate(PC) plate lying on an earthed metal plate (back electrode), the opposite electrode being connected to the back by: 2.

The research on vacuum surface flashover mechanism of insulating material under steep high voltage impulse is important for the design and manufacture of high power pulse generator.

This report studies the vacuum surface flashover characteristic of epoxy composite material with different fillers is studied. Generally, various kinds of micron-sized inorganic fillers are utilized to promote.

While surface flashover in vacuum is generally undesirable, it is necessary for the operation of triggered vacuum gaps, i.e. the “switch” for many pulse power systems. Much has been written about the mechanisms by which triggered vacuum gaps operate and many ingenious designs have been described [.

The recent visit of Dave Hammer from NRL gave me occasion to analyse roughly the available small sample flashover data and I thought the results might be of minor interest to others.

This re-analysis has been directed towards the region of interest to tube designers and concentrated on perspex (i.

lucite) at about 45°, where it withstands Cited by: Ambient neutral densities, immediately above the insulator surface, in the initial stages of flashover have been calculated to lie in the range from 2×10 1 7 /cm 3 to 2×10 2 1 /cm 3 with a mean of about 1×10 1 9 /cm 3, whether flashover occurred on surfaces in air at atmospheric pressure or Cited by: @article{osti_, title = {Time- and space-resolved light emission and spectroscopic research of the flashover plasma}, author = {Gleizer, J.

and Krasik, Ya. and Leopold, J.}, abstractNote = {The results of an experimental study of the evolution of surface flashover across the surface of an insulator in vacuum subject to a high-voltage pulse and the parameters of the flashover.

Data are obtained from surface discharge experiments are consist of: 1) video frames (including high-speed photography) 2) the pulse shape of the applied voltage 3) oscillograms of electric current 4) the surface charge density and electric field on the surface of the insulator 5) dust (Lichtenberg) Size: KB.

Under the high electric field, discharge sometimes occurs along the surface of solid in vacuum, gas or liquid dielectrics, which is called surface 2-B2O3-K2O-Li2O-Al2O3-ZnO-MgO-F system glass ceramics has great machinability and excellent dielectronic paper tries to study different time of ion-exchanged samples and their microstructures,which affect surface Author: Peng Zhai, Xin Pei Ma, Nan Zheng.

The dc surface flashover phenomena in relatively high vacuum (10** minus **** minus **7 torr) is studied using polyethylene samples. Based on the results of the investigator, the following possible discharge mechanism is proposed, First, electrons are emitted from the cathode-dielectric by:   Prior to the flashover across an insulator in vacuum, the insulator surface is usually charged.

It is of great importance to investigate the charging phenomena for better understanding the flashover characteristics. It is considered that there are two kinds of mechanisms closely related to the surface charging of insulator i.e., the secondary electron emission occurred over an insulator, and.

A study of pulse surface flashover in a vacuum [microform] / by Vishnukumar K. Lakdawala The Journal of Canadian petroleum technology Journal of vacuum science & technology. Experiments on the vacuum flashover of dielectric frusta subjected to 35 and 75 nsec pulses show the strong influence of cone angle on insulation strength.

A theory is presented to explain the formative process leading to flashover for one polarity. It is proposed that positive surface charge grows by emission of hot electrons during the application of the electric by: Cite this chapter as: de Tourreil C.H. () Surface Flashover Voltage of Spacers in Vacuum at Cryogenic Temperatures.

In: Timmerhaus K.D., Reed R.P., Clark A.F Cited by: 3. "A Study of Pulsed Surface Flashover in a Vacuum" $3, May, - May, Lakdawala, V.

K.; Radhakrishnan, D. "Easily Testable Designs and Device Modeling for VLSI" $25. “Vacuum and Surface Science” is an academic journal published by The Japan Society of Vacuum and Surface first issue was published in January, The predecessor journals are “Journal of the Vacuum Society of Japan (JVSJ)” and “Hyomen Kagaku (Journal of the Surface Science Society of Japan)”.The journal is aiming to expand into new fields while following the article.Surface flashover fields of 5 - 30 kV/cm are common in silicon-vacuum systems, even though the intrinsic critical fields of silicon and vacuum are > kV/cm.

The influences of the material (bulk quality and surface processing), contact technology, contact geometry and electrode configuration on the preflashover and surface flashover Cited by: 2.In low pressure reactors, for which the mean free paths of reactive particles are of the order of plasma chamber dimensions, the chemical equilibrium of the gas phase is strongly dependent on surface chemistry.

Unfortunately data on elementary surface processes are often not available, particularly for surfaces exposed to plasma conditions. In this work such data are obtained through a time Cited by: