A simulation of breakdown parameters of High Power Microwave induced plasma in atmospheric gases

Patrick J. Ford, John Krile, Hermann Krompholz, Andreas Neuber

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

1 Scopus citations

Abstract

Surface flashover induced by a High Power Microwave fast rise-time pulse causes a significant drop in transmitted power, along with reflections that can damage the source. Momentum transfer collision rates in the range of 100s of GHz (for pressures exceeding 5 kPa) lead to low plasma conductivity, corresponding to absorption levels of up to 60 % of the incident power. A simulation algorithm was developed using the finite-difference time-domain (FDTD) method in order to model the growth and transport of the electron density near a dielectric surface, and the resulting interaction with the microwave pulse. The time-dependent plasma parameters are governed by empirical and simulated scaling laws for ionization and collision rates, along with diffusion coefficients; the resulting frequency-dependent plasma permittivity is transformed to a discrete algorithm to describe the spatially resolved plasma in the FDTD algorithm. A plasma thickness of up to 2 mm is simulated that compares with side-on ICCD imaging of surface flashover. Breakdown parameters, such as delay times and breakdown electric fields, in nitrogen, air and argon, are compared with experimental data on surface flashover across a polycarbonate window at atmospheric pressures; the simulated results correlate well with measured, and the model exhibits low computational complexity when simulating a pulse on the order of microseconds, making it a good alternative to standard particle-in-cell codes. The source is a S-band magnetron that produces a 2.5 MW peak power, 50 ns rise-time pulse with 3 μs duration at 2.85 GHz center frequency.

Original languageEnglish
Title of host publicationProceedings of the 2012 IEEE International Power Modulator and High Voltage Conference, IPMHVC 2012
Pages272-275
Number of pages4
DOIs
StatePublished - 2012
Event2012 IEEE International Power Modulator and High Voltage Conference, IPMHVC 2012 - San Diego, CA, United States
Duration: Jun 3 2012Jun 7 2012

Publication series

NameProceedings of the 2012 IEEE International Power Modulator and High Voltage Conference, IPMHVC 2012

Conference

Conference2012 IEEE International Power Modulator and High Voltage Conference, IPMHVC 2012
CountryUnited States
CitySan Diego, CA
Period06/3/1206/7/12

Keywords

  • FDTD
  • Low temperature plasma
  • Microwave breakdown

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