Pseudospark Discharge To Produce The Theoretical Simulation Of The Electron Beam

The high power electron beam source technology, as a new technology, has been developed quickly because of the continuing demands of higher power, higher energy microwave sources in military and scientific research in recent years. The pseudospark electron gun works at high voltage and can produce high power electron beam. The ions produced by discharges do not bomb the cathode directly. With so many advantages, the pseudospark electron gun is prospective to be a new kind of beam source. However, the principle of pseudospark discharge is still not very clearly. In order to enhance the high power electron beam more clearing. In the dissertation, the properties of pseudospark discharge and the focusing effect of plasma is studied. The main works and the major achievements are listed as following:1. Outlining the characteristics of the pseudospark electron gun and the basal discharge theory of the pseudospark structure, the development about the pulsed electron beam technology, the shortcomings of emission cathode. Study on the cathode and electron gun's purposes are two, one is to increase the current density about the electron beam, the other one is better control of beam for reducing the formation of excess plasma.2. The pseudospark hollow cathode discharge is described with a fluid method which composed of the electron and the positive ion continuity equation, the Possion and the moment of the Boltzmann equations. The discretization of all the above equations and the variables-the electron and the positive ion density, the electric potential, the average electron energy on the central axes and the boundary are described in detail. The fluid method about the psiudospark is established finally.3. The fluid model of initial pseudospark discharge is formulated and calculated numerically and theoretically under local field approximation in the low pressure. The FDTD method is adopted and the calculational programme is used by the language of the MATLAB. Got the distribution of the electric field, electrons, ions and the electric field formation, electrons, ions growth at low pressure. The initial pseudospark discharge is described for four discharge stages. The virtual anode formation time and propagation velocity at apertures are investigated. The results show that there exists a hollow cathode discharge effect, which plays a more important role in initial discharge at low pressure in the pseudospark discharge process. And also indicate that the fluid model used in the pseudospark discharge is a available method and has its advantages compare to the other methods.