Study of the dynamics of a sheet electron beam in miniature W-band TWT with permanent magnet focusing systems
Alina D. Tolstykh1,2, Roman A. Torgashov1,2; 1Saratov Branch Kotel'nikov Institute of Radioengineering and Electronics RAS, Russia; 2Saratov State University
Abstract
Miniature sheet-beam traveling-wave tubes (TWTs) is promising device to operate in millimeter band with high output power and wide operating frequency band. However, the key problem in developing of such devices is providing of stable beam transport over distances of up to 10 cm using magnetic focusing systems.
In this work, the study of the dynamics of a 500×100-μm² 100-mA 14.6-kV sheet electron beam in the tunnel of a miniature TWT with astaggered double grating slow-wave structure (SWS) using 3D COMSOL Multiphysics simulation is presented. At the first stage, the case of uniform magnetic field focusing along the electron beam direction is considered. It is shown that in this case, the electron beam is characterized by diocotron instability. To prevent electrons settling on the surface of the SWS, magnetic fields of at least 0.8 T are required. But such a magnetic system is characterized by big mass and dimensions.
To achieve miniaturization of the device and stable beam focusing, there is an approach that involves the use of magnetic periodic focusing systems. In this case, the magnetic field has a more complex configuration. The dynamics of the electron beam were studied and the required magnetic field configuration was obtained. It was shown that stable beam transport over the interaction space is observed at peak magnetic field values on the beam axis of 0.15-0.16 T with a magnetic system period of 7 mm.
This work is supported by the Russian Science Foundation under grant # 25-72-00050.
Speaker
Alina Tolstykh
Saratov State University
Russia
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