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.