Measurement of Toroidal Structure of Electron Temperature with Electron Cyclotron Emission Diagnostic in JT-60U

A new transmission line for electron cyclotron emission (ECE) diagnostic has been introduced in order to improve a signal-to-noise ratio and to observe the structure of electron temperature in the toroidal direction. Installation and calibration have been finished as planned. It is found that a signal-to-noise ratio of a heterodyne radiometer is improved by a factor of >5, and that toroidal mode number can be identified by comparing ECE signal from the new transmission line with that from the existing transmission line located 60 degrees apart in the toroidal direction. Also, both toroidal and poloidal structures have been observed during a large collapse in a reversed shear discharge by the simultaneous measurement