Coaxial vircator source development

Summary form only given. A study of efficiency improvement for a coaxial virtual cathode oscillator is described. The coaxial geometry has many physical parameters that can be changed to alter the performance of the system. The parameters of interest include diode length, anode-cathode gap spacing, and an electron absorbing collection rod. The center rod also has two changeable variables, rod length and rod radius. The rod radius appears to be the critical parameter. Making the radius too large results in too many electrons being collected resulting in a decrease in produced microwaves, making the radius too small results in little effect compared to the no-rod case. MAGIC, a 2.5D particle-in-cell code, is used to simulate the different geometries. Conclusions on varying the parameters are given.