Gyrotron collective Thomson scattering diagnostic for confined alpha particles in TFTR

A 200‐kW, ∼60‐GHz gyrotron will be used on TFTR during D–T operation for collective Thomson scattering diagnostics of confined alpha‐particle velocity distribution and density. Scattering angles of up to 120° are under consideration using x‐mode propagation to increase the density cutoff limit. Useful signal‐to‐noise ratios will be possible in plasmas where ne≳5×1013 cm−3, nα≳2×1011 cm−3, and the background emission is ≲30 eV equivalent blackbody level.