There are a number of important nonlinear processes that are being studied for the high-power gyroklystron amplifiers that are under development at the University of Maryland. These amplifiers are intended to be used in the next generation of high energy particle accelerators. The principle nonlinear process in the microwave circuit involves the interaction of the electron beam and electromagnetic modes in resonant cavities. Student projects involve both the development of better modeling tools for the large-signal behavior and use of the nonlinear codes to design, construct, and test the performance of components. Undergraduates have contributed significantly to projects in this group, co-authoring 7 papers in the last 5 years.

Two projects which could involve undergraduate participation are the following:

• The study of the competition of multiple modes in the output cavity, and the examination of the role of controlled losses on multi-mode effects and nonlinear mode suppression.

• The investigation of the mode transducers and tapers in the microwave output waveguide which are necessary to transport the energy and transform the electromagnetic field configuration into one suitable for injection into a linear accelerator.

Additional information about nonlinear processes in gyroklystron systems can be found at http://www.ireap.umd.edu/gkl and by contacting Professor Lawson at (301)405-4972 or lawson@umd.edu.