Intense Relativistic Annular Electron Beam Self-modulation Oscillation Theory And Particle Simulation

In this paper, the analysis for this mechanism that self-modulation may appearwhile an intense relativistic annular electron beam is going across a foil and enter intoan equipotential resonant cavity is presented. Employed a theory of space-charge effectunder small signal condition, we got the frequency of self-disturb. Based on thismechanism, a new type of high power microwave source and PIC simulation are given.While an intensely relativistic electron beam is going across an equipotentialresonant cavity, because of the space charge effect, a static electric field should beformed in the cavity, and an annular static magnetic field should be formed by theintense relativistic annular electron beam itself at the same time. The strong electricfield and magnetic field will cause the electron beam to self-disturb in the equipotentialresonant cavity. In this paper, the space-charge limiting current of cylinder waveguide isderived by the second-equation of Green's. we employed the equation of Poisson, to getelectrostatic potential, then analysis for self-disturb may appear while an intenserelativistic annular electron beam is going across a foil and enter into an equipotentialresonant cavity are presented. At last 2.5D PIC numerical was conducted to study it.After optimization design, a 1.7GW output peak microwave power was observed at afrequency of 4.44GHz, while an electron beam of current 13.5kA, voltage 1.29MV isinjected. The cavity's length is 4.5cm. The efficiency is about 10%.