Effects of electron beam pinching on microwave emission in a vircator

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:170196

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

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

Electron beam pinching in relativistic diodes has been widely observed. This pinching of electrons is understood to be caused by the flow of ions from the anode together with the flow of electrons from the cathode. The anode flow is created by the heating of the anode by the electron beam. Such a counter flow of electrons and ions is known as a bipolar flow. A vircator experiment at the Himeji Institute of Technology suggested that microwave emission in the vircator was due to a strongly pinched electron beam caused by bipolar flow. A MAGIC particle-in-cell simulation is being developed to study the effects of electron beam pinching on microwave emission in a vircator. Cathode emission from an annular cathode is modeled in the simulation by placing a plasma on the surface of the cathode and an electric field is applied to accelerate the electrons extracted from the plasma. To model the anode emission, the anode is divided into segments. The ion current is then taken to be a fraction of the electron current through each segment. Preliminary results suggest that the pinched electron beam would form a larger virtual cathode potential inside the waveguide behind the diode which should enhance microwave production. The effect of an axially applied magnetic field will also be studied to determine if the magnetic field would suppress electron pinching and microwave emission as was observed in the Himeji experiment.

• OSTI ID: 170196
• Report Number(s): CONF-950612--; ISBN 0-7803-2669-5
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
BEAM DYNAMICS
COMPUTERIZED SIMULATION
ELECTRON BEAMS
ELECTRON DRIFT
ION DRIFT
MICROWAVE EQUIPMENT
PERFORMANCE