Development of the W-band density profile and fluctuation reflectometer on EAST

•A X-mode W-band reflectometer is designed and installed on Experimental Advanced Superconducting Tokamak (EAST) for the first time.•Both density profile and fluctuations can be measured by the newly developed reflectometer.•The core density profile has been measured in high magnetic field condition together with V-band reflectometer.•Sawtooth precursor has been measured by fluctuation reflectometer in the low magnetic field condition.

A X-mode polarized W-band reflectometer for plasma density profile and fluctuation measurement is designed and installed on EAST. In measuring the density profile, a voltage controlled oscillator (VCO) is used as the source, allowing a high temporal resolution measurement. The density profile in a plasma with high magnetic field (3.0 T) has been measured by combination of V- and W-band reflectometers. For fluctuation measurements, a frequency synthesizer is used instead of the VCO as a microwave source. The core density fluctuations during sawtooth activity are measured and analyzed.