Recent Advances from the DoD Multidisciplinary University Research Initiative Consortium on Innovative Vacuum Electronics

The MURI Innovative Vacuum Electronics Program is administered by Dr. Robert Barker of the Air Force Office of Scientific Research and consists of a collaboration between six premier universities actively engaged in all aspects of multidisciplinary basic research and graduate instruction in innovative microwave vacuum electronics (MIT, Stanford, University of California, Davis, University of Maryland -- College Park, University of Michigan, and University of Wisconsin). The dual goals are to address basic research issues of critical importance to the DoD as well as to train the next generation. A wide range of fast wave amplifier concepts is under investigation at frequencies ranging from 15 GHz to 1 THz. Two representative examples are a TE01 100 kW W-Band gyro-TWT under investigation at UC Davis and a 140 GHz confocal waveguide based gyro-TWT concept developed at MIT. Novel, lightweight 100 kW, W-Band klystrinos suitable for configuration in arrays are under investigation at Stanford using advanced microfabrication techniques. Extensive analytic and numerical analyses are underway at Wisconsin augmented by experimental measurements using a custom-modified well diagnosed test TWT are aimed at an understanding of the complicated physics of multi-toned ultra-wideband traveling wave tubes including details of the beam-wave interaction and the nonlinear time and space evolution of the carrier(s) and inter-modulation products. A significant emphasis of the Maryland activity is on theoretical and experimental studies of various frequency-multiplying gyroamplifier concepts which are both of fundamental interest as well as practical importance because of the relaxation on driver requirements. Finally, the Michigan team is devoting much of its attention to fundamental theoretical and experimental issues associated with crossed-field devices. The latest results from these as well as other activities will be presented