A tribute to George Bekefi (1925-1995)

A brief biography of George Bekefi (1925-1995) is given highlighting his professional achievements. Bekefi made very significant contributions to the science of radiation in general and to high power microwave (HPM) generation in particular. He, together with his students T. Orzechowski and A. Palevsky, invented the relativistic magnetron in the mid to late 1970\´s. This invention was an important milestone in the development of gigawatt-class microwave sources and is still regarded as a premier high power source in the frequency range 2-6 GHz. The development of the relativistic magnetron also stimulated the development of the MASK code, one of the most popular particle-in-cell codes used today. In addition to these efforts, he made important contributions to our understanding of free electron lasers (FELs), most notably in the Raman regime, to the use of rotating electron beams for coherent radiation production, and to the challenging task of measuring emittance on intense electron beams. In the last several years, he contributed primarily in the areas of relativistic klystrons, cyclotron masers, and microwiggler FELS. Prior to this 20-year period of devotion to the field of high power microwave generation, he made fundamental contributions to our understanding of radiation processes in ionized gases, and he was the author of a classic text in the field, "Radiation Processes in Plasmas" (New York: Wiley, 1966).