The intense electron beam-plasma system serves as an important platform for investigating beam-plasma interactions. Research in this field focuses on the design of electron beam window and the transport characteristics of electron beam in plasma.

The study aims to design and evaluate an electron beam window with excellent comprehensive performance, and to investigate the physical mechanisms underlying the focusing and transmission of intense annular electron beams in plasma.

Finite element analysis and Monte Carlo simulations were employed to compare and evaluate the mechanical, thermal, and transmission properties of candidate window materials. Theoretical analysis and particle-in-cell (PIC) simulations were used to study the self-focusing transmission behavior of intense annular electron beams in plasma.

The TC4 titanium alloy window with a thickness of only 0.04 mm was found sufficient to withstand a pressure differential of 10 kPa. It achieved an energy transmission efficiency exceeding 90% while maintaining controllable temperature variations. The physical mechanism of self-focusing transmission of intense annular electron beams in plasma under conditions of 500 kV and 20 kA was revealed, clarifying the relationship between the focusing transmission period of the electron beam and the plasma density. Furthermore, an equivalent relationship between plasma density and magnetic field was established based on the correspondence between the plasma oscillation period and the electron beam cyclotron period.

The research demonstrates that TC4 titanium alloy is a suitable material for the electron beam window, offering high transmission efficiency and structural stability. It also elucidates the self-focusing transmission mechanism of intense annular electron beams in plasma and establishes a periodic equivalent relationship between plasma and magnetic fields for electron beam transport.