A MAGIC simulation study of the effects of bipolar flow on microwave emission in a vircator

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:51800

Young, D; Ishihara, Osamu ^[1]; Yatsuzuka, M ^[2]

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1. Texas Tech Univ., Lubbock, TX (United States)
2. Himeji Inst. of Tech., Hyogo (Japan)

High-power microwave generation in an axially-extracted virtual cathode oscillator (VIRCATOR) is studied numerically using MAGIC which is a two-dimensional, finite-difference, time-domain particle-in-cell code. The simulation was motivated by the recent experiment of Yatsuzuka et al at the Himeji Institute of Technology in Japan. The Himeji experiment observed that, while pinching of the electron beam was found to be essential for microwave generation, the electron beam current remained below the critical pinching current when microwaves were detected. On the other hand, an earlier experiment by Benford et al showed that microwave emission occurred only when the diode current exceeded the critical current. In the simulation being developed for the Himeji VIRCATOR geometry, the preliminary phase space diagrams show the formation of a virtual cathode. A detailed simulation study is in progress on the effect of bipolar flow on the critical current for beam pinching and microwave emission. Bipolar flow consists of ion flow from the anode into the diode gap in addition to the electron flow and is known to increase the electron space charge limited current.

• OSTI ID: 51800
• Report Number(s): CONF-940604--; ISBN 0-7803-2006-9
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
COMPUTERIZED SIMULATION
DYNAMICS
FINITE DIFFERENCE METHOD
M CODES
MICROWAVE AMPLIFIERS
NUMERICAL ANALYSIS