St Andrews Research Repository

St Andrews University Home
View Item 
  •   St Andrews Research Repository
  • Physics & Astronomy (School of)
  • Physics & Astronomy
  • Physics & Astronomy Theses
  • View Item
  •   St Andrews Research Repository
  • Physics & Astronomy (School of)
  • Physics & Astronomy
  • Physics & Astronomy Theses
  • View Item
  •   St Andrews Research Repository
  • Physics & Astronomy (School of)
  • Physics & Astronomy
  • Physics & Astronomy Theses
  • View Item
  • Login
JavaScript is disabled for your browser. Some features of this site may not work without it.

Low pressure plasmas for high power microwave sources

Thumbnail
View/Open
PeterFrankHirstPhDthesis.pdf (27.10Mb)
Date
07/1992
Author
Hirst, Peter Frank
Supervisor
Maitland, Arthur
Metadata
Show full item record
Altmetrics Handle Statistics
Abstract
This thesis describes an investigation of the use of low pressure plasmas for the generation of high power microwaves. Previous research has shown that the efficiency of a high power microwave ("HPM") source such as a BWO is enhanced by the introduction of a low pressure plasma into the oscillator cavity. The principle aim of this thesis is to extend the use of low pressure plasmas to the whole HPM system. Electron beams with current densities of the order of 20 A cm-2 can be generated in a cold cathode glow discharge at low gas pressures. Results are presented which show the effects of magnetic fields and electrode spacing on the I-V characteristics of a DC glow discharge electron gun. A glow discharge electron gun with an operating voltage of 350 kV has been designed and tested. A new kind of RP plasma cathode is proposed in which electrons are drawn from an RF discharge in a low pressure gas. An analysis of the production of an annular RF plasma cathode using a microwave-excited helical slow-wave structure is presented. Experimental results show that the RF plasma cathode yields electron current densities an order of magnitude higher than does a solid cathode. Examples of the implementation of the RF plasma cathode in a number of components of an HPM system are given. The propagation of electromagnetic waves in plasma-loaded waveguides of circular cross-section has been modelled. Numerical solutions are presented for the case of slow-waves in a longitudinally-magnetised plasma waveguide. Propagation below the cut-off frequency of the waveguide is generally possible and, according to the configuration, the propagating waves may be used for plasma generation or for RF power transmission. A new kind of high power microwave waveguide switch, based on the properties of plasma waveguides, is proposed. The design of new kind of magnetron, the "Glow Discharge Inverted Magnetron" ("GDIM"), is presented. The GDIM is an inverted magnetron with the resonant structure located on the cathode. The resonant cavities are used as a source of glow discharge electron beams, which gives high power operation without requiring relativistic voltages.
Type
Thesis, PhD Doctor of Philosophy
Collections
  • Physics & Astronomy Theses
URI
http://hdl.handle.net/10023/13613

Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

Advanced Search

Browse

All of RepositoryCommunities & CollectionsBy Issue DateNamesTitlesSubjectsClassificationTypeFunderThis CollectionBy Issue DateNamesTitlesSubjectsClassificationTypeFunder

My Account

Login

Open Access

To find out how you can benefit from open access to research, see our library web pages and Open Access blog. For open access help contact: openaccess@st-andrews.ac.uk.

Accessibility

Read our Accessibility statement.

How to submit research papers

The full text of research papers can be submitted to the repository via Pure, the University's research information system. For help see our guide: How to deposit in Pure.

Electronic thesis deposit

Help with deposit.

Repository help

For repository help contact: Digital-Repository@st-andrews.ac.uk.

Give Feedback

Cookie policy

This site may use cookies. Please see Terms and Conditions.

Usage statistics

COUNTER-compliant statistics on downloads from the repository are available from the IRUS-UK Service. Contact us for information.

© University of St Andrews Library

University of St Andrews is a charity registered in Scotland, No SC013532.

  • Facebook
  • Twitter