Lowered plasma velocity with cesium iodide/carbon fiber cathodes at high electric fields

Summary form only given. When explosive emission cathodes are used in higher power (>100 MW) devices, microwave pulse shortening occurs because of motion of the cathode plasma at speeds 1 to 5/spl times/10/sup 6/ cm/sec. This limited duration in turn can limit present-day high power microwave (HPM) sources to a few hundred joules. The introduction of cathodes made from cesium lodide-coated (Csl) carbon fiber has shown reduced plasma velocity reduced by factors of a few from uncoated carbon fiber, but previous work was at low diode fields of a few 10´s of kV/cm. We have demonstrated reduced Csl plasma velocity for macroscopic electric fields of 265 kV/cm, sufficient for the diodes of GW microwave sources.