Contribution of Ne ions to radiation enhancement in JT-60U divertor plasmas

Nakano, Tomohide; Asakura, Nobuyuki; Kubo, Hirotaka; JT-60 Team

Journal of Nuclear Materials, 438, p.S291 - S296, 2013/07

https://doi.org/10.1016/j.jnucmat.2013.01.049

It is already concluded that neon injection is more effective than argon injection in order to enhance the radiative power from the divertor plasmas in JT-60U. In this study, we have investigated radiation processes of neon ions in low-temperature and high-density divertor plasmas with spectroscopic technique. It was observed that the emission intensities of Ne VII spectral lines became high during plasma detachment. A collisional-radiative model analysis with the intensity ratio of Ne VII emission lines gave an electron temperature of 100 eV and a radiative power of only 5% of total radiative power, measured with a bolometer. Because C IV emission intensity was low, it is probable that the radiative power of C IV was also low. Therefore, it is possible that neon and carbon ions at other charge states contribute much to the total radiative power from the divertor plasma.