The influence of a DC electric field on high power microwave window flashover in air and N2 environments

J. Foster, M. Thomas, H. Krompholz, A. Neuber

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Observed delay times for high power microwave surface flashover are influenced significantly by the presence of a DC electric field. The experimental setup to investigate theses influences is comprised of an S-band magnetron operating at 2.85 GHz with a pulse rise time shortening switch assembly that produces a 50 ns rise time at a ∼ 2.5 MW power level. A wire electrode charged to ±20 kV is inserted into the dielectric interface perpendicular to the electric field of the TE10 mode to provide a DC electric field in the flashover region. Tests have been conducted in pure N2 at 125 torr in order to provide an environment composed of primarily electrons and positive ions. The average measured delay of window flashover with a DC field pointing into the dielectric has been observed to increase by ∼50%. Additionally, effective emission rates of seed electrons initiating breakdown have shown a decrease from 14 e/μs to 2 e/μs, indicating the removal of charged species from the high microwave field region due to charge drift in the applied DC field. An overview of the experimental setup is given along with a statistical analysis of delay times measured in Air as well as N2. The open question of where seed electrons originate from and the quantification of the primary processes involved will be addressed.

Original languageEnglish
Title of host publicationPPC2009 - 17th IEEE International Pulsed Power Conference
Pages480-483
Number of pages4
DOIs
StatePublished - 2009
Event17th IEEE International Pulsed Power Conference, PPC2009 - Washington, DC, United States
Duration: Jun 28 2009Jul 2 2009

Publication series

NamePPC2009 - 17th IEEE International Pulsed Power Conference

Conference

Conference17th IEEE International Pulsed Power Conference, PPC2009
CountryUnited States
CityWashington, DC
Period06/28/0907/2/09

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