Investigation of phase modulation and propagation-route effect from unmatched large-scale structures for Doppler reflectometry measurement through 2D full-wave modeling

To interpret the common symmetric peaks caused by the large-scale structure in the complex S(f) spectrum from the heterodyne Doppler reflectometry(DR) measurement in EAST, a 2D circular-shaped O-mode full-wave model based on the finite-difference time-domain method is built. The scattering characteristics and the influences on the DR signal from various scales are investigated. When the structure is located around the cutoff layer, a moving radial or poloidal large-scale structure k_θ■...     

Evaluation of NBI absorption and fast ion stored energy to improve thermal energy confinement time calculation in EAST

The absorption of neutral beam power and the fast ion stored energy in EAST plasmas with neutral beam injection(NBI)is analyzed to improve the calculation of thermal energy confinement time.The neutral beam power absorption and fast ion stored energy are systematically calculated using the TRANSP code,through the investigation of global parameters including plasma current,line averaged density and beam energy.Results have shown that scaling laws for the NBI absorption coefficient and fast ion energy rate are obtained through statistical analysis.A comparison of the confinement improvement factor H98y2 with these new scaling laws against those assuming fixed coefficients is given.