Simulation of beam collector heating patterns in small-orbit gyrodevices

Summary form only given. An important issue in the development of high average power gyrodevices is the design of the electron beam collector, which typically can handle local, time-averaged power densities of 0.5-1.0 kW/cm/sup 2/. The spiraling beams employed in gyrodevices can create zones of enhanced local heating in the collector as a result of the turning-point behavior of the electron orbits, a situation which is not found in conventional linear beam amplifiers. Nevertheless, with careful tailoring of the axial magnetic field profile in the collector region, a fairly uniform heating pattern in the collector can be achieved. The procedure for producing simulated collector maps will be illustrated using a 10 kW average power, 94 GHz gyroklystron as an example. The computed effects of angular and transverse collector misalignments and other beam asymmetries will be presented. The simulations will be compared with experimentally observed heating patterns.