Microwave scattering diagnostic on the Advanced Toroidal Facility torsatrona)

A 2 mm scattering diagnostic used to study density fluctuations of the electron cyclotron resonance heated plasma in the Advanced Toroidal Facility is described. A four‐channel flexible antenna design was chosen to monitor fluctuations within the wave number range of 3gyrotron used for plasma heating. This spurious signal was suppressed using waveguide filters and rearrangement of the microwave circuit elements. Evidence in support of direct scattering from a well‐defined plasma volume was found. Good correlation of the scattered waves’ intensity with the density scale length was observed. Use of a dual‐homodyne circuit configuration made is...