FIR interferometer/polarimeter system on ISX-B tokamak

Recent results of simultaneous measurements of electron density and Faraday rotation on all five channels of the FIR interferometer/polarimeter system on ISX‐B are presented. The time resolution of the interferometer is typically 1 μs. The standard deviation of the output of the interferometer of a constant phase shift is less than 5×10−2 fringe, corresponding to a line electron density of 5×1011 cm−3. The polarimeter shows a sensitivity of the order of 1 mrad and a time resolution of approximately 1 ms. Data are reported on ohmic as well as neutral‐beam‐heated plasmas including solid hydrogen pellet injections. It is believed that this is the first successful measurement of Faraday rotation in pellet‐injected discharges. Data analysis codes have been developed and the results are being compared with other measurements.