PREDICTED EMITTANCE AND BRIGHTNESS OF THE PSEUDOSPARK ELECTRON-BEAM

The emittance and brightness of the electron beam generated during the hollow cathode phase of pseudospark operation are calculated using th e two-dimensional hybrid fluid-particle model previously developed to study the time and space development of the plasma in a pseudospark di scharge. Two distinct energy components exist in the electron beam; a high-energy component with an energy equivalent to the full discharge voltage and another, broad, low-energy component. In the 100 ns follow ing breakdown and for the conditions of the calculations, the emittanc e of the high energy component decreases by an order of magnitude and the brightness of the high energy component reaches almost 10(10) A/m( 2) rad(2). This work demonstrates the feasibility of using the model t o guide the optimization of the pseudospark electron beam properties a nd shows that the optimum beam properties are achieved after the plasm a has filled the hollow cathode and begun to expand radially in the ma in gap.