Study Of Electron Heat Conductivity In H-mode In EAST

In future ITER device, α particles produced by nuclear fusion will mainly heat electrons, so the research on electronic transport is very important. Electronic thermal transport in typical shots of high-confinement (H-mode) achieved with Lower Hybrid Wave (LHW), LHW and ICRF (Ion Cycle Radio Frequency) are studied in this paper on EAST. Energy balance is analyzed by TRANSP code with experimental data. The electronic thermal conductivity during H-mode significantly drops comparing with that during L-mode, especially in the edge area (p>0.7). The central radiated power increases significantly and the LHW power deposition shifts to the plasma periphery, which result in the decrease in electronic thermal flux for power balance analysis during H-mode. The position of deposition in LHW affects the electron conductivity profile more obviously when the power of LHW is much larger than the power of ICRF in H-mode.An empirical model for electronic thermal transport based on the existence of a normalized temperature gradients threshold R/LTe has also been discussed for these typical shots in this paper. By analyzing the relationship between normalized diffusion coefficient and normalized temperature gradient, the threshold of R/LTe is from 3 to 11 in these shots. Energy confinement times are also estimated in these shots. There is some difference between the data evaluated by ITER scaling law and the data calculated by TRANSP. Results are helpful for understanding electron heat transport and offer references about plasma confinement on EAST tokamak.