Radial Density Profiles of Highly Ionized Metallic Impurity Ions in RF-Heated H-Mode Plasmas in EAST

Spectral intensities emitted from high-Z metal impurity ions of Fe22+ at 132.91 angstrom, Mo30+ at 115.999 angstrom, Mo31+ at 127.868 angstrom, W42+ at 129.41 angstrom, W43+ at 126.29 angstrom, and W45+ at 126.998 angstrom and their radial profiles have been observed in EAST plasmas using a space-resolved extreme ultraviolet (EUV) spectrometer. Local emissivity profiles of the emission lines are obtained from the line-integrated profile through the Abel inversion based on the magnetic equilibrium calculation from the equilibrium fitting (EFIT) code. Then, the density profile is analyzed for Fe22+, Mo31+, W43+, and W45+ ions in the L- and H-mode plasmas with lower hybrid wave (LHW) or electroncyclotron-resonance (ECRH) heating using measured electron temperature and density profiles and photoemission coefficients (PECs) from the ADAS database. It is found that the density profile of Fe22+, W43+, and W45+ ions has a peak value of 0.48 x 10(8), 2.34 x 10(8), and 1.55 x 10(8) cm(-3) at p = 0.13-0.17 in the LHW and ECRH-heated L-mode plasmas, respectively. In the H-mode plasma with higher ECRH power, on the other hand, the peak position in the density profile outwardly shifts toward radial positions of p = 0.20-0.26. The density profiles also show an increase in the peak value in comparison with the L-mode plasma case, i.e., increases to 0.7, 2.8, and 1.7 x 10(8) cm(-3) for Fe22+, W43+, andW(45+) ions, respectively. When the ICRF heating is applied to the H-mode plasma, the peak density significantly increases, i.e., 0.9, 3.6, and 2.3 x 10(8) cm(-3) for Fe22+, W43+, and W45+ ions, respectively.

Automated summary

The spectral intensities emitted by high-Z metal impurity ions in EAST plasmas have been investigated, and their radial profiles have been analyzed. The density profiles of these ions under different heating conditions have also been studied, revealing their behavior.