POLOIDAL MAGNETIC-FIELD MEASUREMENTS ON TEXT-UPGRADE

A polarimetry capability has been added to the UCLA multichord far-inf rared heterodyne interferometer system on TEXT-Upgrade. The polarimete r utilizes a phase technique in order to measure the Faraday rotation angle of the incident laser beam upon transmission through the plasma. From these data one derives information on the poloidal magnetic fiel d, current density and safety factor profiles. The response of these p rofiles to electron cyclotron resonance heating and fast current ramps is investigated.