Turbulence analyses of improved electron energy confinement in H-mode plasmas with gyrokinetic calculations

ジャイロ運動論コードを用いたHモードプラズマの電子エネルギー閉じ込め改善に関する乱流輸送研究

成田 絵美; 本多 充; 林 伸彦; 滝塚 知典*; 井手 俊介; 伊丹 潔; 諫山 明彦; 福田 武司*

Narita, Emi; Honda, Mitsuru; Hayashi, Nobuhiko; Takizuka, Tomonori*; Ide, Shunsuke; Itami, Kiyoshi; Isayama, Akihiko; Fukuda, Takeshi*

In burning plasmas, the electron temperature is expected to exceed the ion temperature because of the alpha heating. The transport simulations showed that an increase in degrades the confinement. However in the International Global H-mode Confinement Database, there are data that have the factor exceeding unity in the region. This high can be attributed mainly to the improved electron confinement. The conditions required for the improvement have been investigated with the local flux-tube gyrokinetic code GS2. When the ion temperature gradient length is shorter than the electron one, ion temperature gradient (ITG) mode is dominant, whereas trapped electron mode (TEM) is stabilized. Under this situation, the electron heat diffusivity is suppressed. In addition, an increase in the magnetic shear also decreases the electron heat transport in the positive shear range.