First results from H-mode plasmas generated by ICRF heating in the EAST

Abstract

Deuterium high-confinement (H-mode) plasmas, lasting up to 3.45 s, have been generated in the EAST by ion cyclotron range of frequency (ICRF) heating. H-mode access was achieved by coating the molybdenum-tiled first wall with lithium to reduce the hydrogen recycling from the wall. H-mode plasmas with plasma currents between 0.4 and 0.6 MA and axial toroidal magnetic fields between 1.85 and 1.95 T were generated by 27 MHz ICRF heating of deuterium plasma with hydrogen minority. The ICRF input power required to access the H-mode was 1.6–1.8 MW. The line-averaged density was in the range (1.83–2.3) × 1019 m−3. 200–500 Hz type-III edge localized mode activity was observed during the H-mode phase. The H-mode confinement factor, H98IPB(y, 2), was ∼0.7.

Full wave simulations of fast wave efficiency and power losses in the scrape-off layer of tokamak plasmas in mid/high harmonic and minority heating regimes*

“…The heating scheme in EAST is the same hydrogen minority heating used in Alcator-C-Mod [30]. To have a wide comparison between different devices, we follow the same exercise performed for NSTX/NSTX-U, DIII-D, and Alcator C-Mod.…”

“…Note that FW experiments in DIII-D are in the mid/high harmonic regime [29], while in C-Mod and EAST they are in the minority heating regime [30]. …”

Effect of the scrape-off layer in AORSA full wave simulations of fast wave minority, mid/high harmonic, and helicon heating regimes

“…Note that FW experiments in DIII-D are in the mid/high harmonic regime [7], while in C-Mod and EAST they are in the minority heating regime [8]. DIII-D results.…”

Modeling of the control of the driven current profile in ICRF MCCD on EAST plasma

“…The full-wave method 32 offers a full-wave solution of the finite Larmor radius wave equations adopting the hot plasma dielectric tensor and provides reliable physics for ICRF mode conversion and MCW absorption. 25,[27][28][29] To describe the MCW, large Larmor radius effects need to be considered.…”

“…The ICRF system can deliver 12-MW 1000-s radiofrequency (RF) power to plasma. [32][33][34] Experiments at higher ICRF power are to be performed in the next experimental campaign, and the main goal of the EAST ICRF program is control of the current profile. 34 ICRF MCCD will surely be applied to EAST as a valuable complement owing to its potential for current profile control and satisfactory current drive CD efficiency.…”