Theoretical research and simulation on focusing sheet electron beam with periodic elliptical solenoid

Stable sheet electron beam transport or focusing is critical for the sheet electron beam vacuum electronic device (VED) which is a kind of promising high power device in millimeter and sub-millimeter wave band. This paper proposes a periodic elliptical solenoid structure for the transport of high-elliptical sheet electron beams. The magnetic field of the elliptical solenoid is analyzed, and the conditions for the stable transport of sheet beams in the structure are derived. Particle-in-cell simulations are conducted and verify the conditions.