Theoretical Study On Plasma-Filled High-Power Microwaves And It's Interrelated Problems

Recently, much attention has been attracted to the study of plasma-filled high- power microwave devices for efficiency and output power enhancement. The introduction of plasma into generators of coherent electromagnetic radiation potentially has several beneficial effects including (a) charge neutralization, allowing operation above the vacuum space-charge limiting current, (b) enhanced generation mechanisms involving the plasma electrons, (c) frequency tunability, and (d) operation without a guiding magnetic field. In this paper, theoretical study on plasma-filled high-power microwaves, including the corrugated wageguide structure and free-electron laser, and their interrelated problems have been made. The main works are the following: 1. The effects such as ion-channel, spatial charge and current limiting, Bennett pinch effect, etc. when relativistic electron-beam transporting in plasma have been overviewed. 2. The self-consistent linear theory of electromagnetic radiation from a magnetized plasma-filled backward wave oscillator with sinusoidally corrugated slow-wave structure driven by a solid intense relativistic electron beam has been given. The more general dispersion relation has been obtained without and with considering the ion-channel effect. 3. An alternative method to analysis an ion-channel guiding helical wiggler free- electron laser has been presented. Electron motion and the axial electron bunching were introduced. The dispersion relation in the high-gain regimes has been derived through this method. From this dispersion relation, the maximum growth rate has been obtained and analyzed for both the Raznan regime and high-gain Compton regime. 4. An overview is given of the concept and basic properties relevant to the laserwakefield acceleratot, the plasma beat-wave accelerator, wakefield acceleratorsdriven by multiple laser pulses, and self modulated laser wakefield accelerator.Recent experimental resultS are also sununarized. Generation mechanism ofplasma wave is indoduced, as well as the trapping and acceleration of electronsin the plasma wave. Some limitS on laser-plasma accelerators are discussedassociated with the futUre prospect of laser-plasma acce1eratOrs.