Effects of different cathode materials on submicrosecond double-gap vircator operation

Anatoli S. Shlapakovski, Tal Kweller, Yoav Hadas, Yakov E. Krasik, Sergery D. Polevin, Ivan K. Kurkan

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The operation of a double-gap S-band vircator has been investigated at submicrosecond duration of a high-current electron beam generated in a planar diode. The experiments were performed at accelerating voltages of ≤ 550 kV and diode currents of up to 17 kA using a radio-frequency cavity with a wide coupling window between its two sections. Three types of cathodes have been studied, namely, metal-dielectric, carbon fiber, and velvet cathodes. The main features of the operation of the vircator using each cathode are analyzed. The microwave pulse duration with the metal-dielectric and carbon fiber cathodes reached ∼ 250 ns at the peak power level of ∼100 MW; with the velvet cathode, a duration of ∼ 400 ns was achieved. It has been found that, in addition to the common limitations of the microwave pulse duration related to the dynamics of the diode impedance governed by the cathode plasma expansion, there is another factor, namely, the anode-cathode gap, which determines the delay at the beginning of the microwave generation. The latter effect is explained by the role of electrons oscillating between the virtual and real cathodes in the generation process. The issue of radiated microwave frequency behavior is discussed as well.

Original languageEnglish
Pages (from-to)1233-1241
Number of pages9
JournalIEEE Transactions on Plasma Science
Volume37
Issue number7 PART 2
DOIs
Publication statusPublished - 26 Jun 2009

Keywords

  • Cathodes
  • High-power microwaves
  • Vircators

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

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