Liu Pukun

How to get a large-amplitude plasma wake wave

The large-amplitude nonlinear plasma wake wave driven by ultra-relativistic electron beams of different lengths and densities is studied using the analytical theory of the ultra-relativistic fluid equations. The approximate analytical solution for the wake wave is obtained and how to obtain large-amplitude wake waves is discussed.

Phase-locking of high power gyrotron oscillator

The phase-locking process is studied for high-power gyrotron oscillator driven by an external signal. The phase-locking nonlinear differential equations are derived, and the condition of phase-locking is shown and analyzed. The phase-locking signal can be introduced after gyrotron oscillates into saturation or before it. Two different ways of inputting signal make markable influence on the phase-locking process, this phenomenon is discussed. In this paper, the numerical calculations and analysis are given for gyrotron TE13 mode.

Two Mechanisms in a Relativistic Electron Cyclotron Maser with a Special Quasioptical Cavity

In a relativistic electron cyclotron maser with an axisymmetrical quasioptical cavity of oblique rotation at arbitrary angle, the rotating angle has a great influence on beam-wave interaction. Two different physical mechanisms are found with the rotating angle ranging from 0° to 90°. One is cyclotron auto-resonance maser regime for small angle, with small optimized external magnetic field; the other is electron cyclotron resonance maser regime for large angle, with comparatively large optimized magnetic field.

Effect of Longitudinal Momentum Spread in Ion-Ripple Laser

Using kinetic coupling mode theory of three waves, the effect of longitudinal momentum spread in ion-ripple laser (IRL), which is an advanced new scheme to generate tunable-coherent radiation with frequency ranging from microwaves to x-rays, is investigated. For a Gaussian distribution in beam longitudinal momentum, the results show that the growth rate of IRL falls off rapidly with increasing momentum spread, and the momentum spread causes linear damping of beam space-charge wave, weakening the beam-radiation mode coupling and lowering the output radiation frequency apart from broadening the radiation spectrum. The dispersion relation and phase matching conditions are also obtained.