Space-charge flow starting conditions in RF-keyed crossed-field amplifiers

The performance of cold-cathode distributed emission crossed-field amplifiers (CFA) used in high power radar systems is degraded because of problems with starting delay, power dips, circuit dissipation and low efficiency. A theoretical analysis has been performed at ECOM which explains the reasons for these difficulties. The key lies in the gross features of the CFA space-charge flow which is completely specifled by two time-independent parameters, the average secondary emission coefficient of the cathode, and the average electron back-bombardment energy. The parameters characterize the emission capability of the cathode and are a function of CFA interaction space geometry, operating conditions and cathode material. The theoretical analysis has been programmed for a digital computer to provide a design and evaluation tool to improve CFA performance.