A two-frequency pulse refractometer for measuring the electron density in tokamaks

An instrument for fringe-jumps free measurements of the electron concentration and estimations of the peaking factor of density distributions in magnetic confinement plasma devices with probing at frequencies close to the cutoff is described. The instrument is intended to perform measurements in a 5 × 1018–1020 m−3 density range (while probing by the extraordinary wave) with time resolution ∼10 μs.