Plasma Scattering Measurement using a Gyrotron as a Radiation Source

High frequency gyrotrons are characterized by their capacity to generate powerful radiation in millimeter to submillimeter wavelength range. However, a gyrotron produces a spreading radiation with a spatial structure of the TEmn circular waveguide mode. Functional quasi-optical systems to transmit and to tune the waist size of Gaussian beam converted from gyrotron output are necessary to the application of gyrotron as a radiation source. Such systems enable us to ensure the effective coupling of beam to sample and waveguide.