T. Minami, S. Okamura, C. Suzuki, K. Matsuo, T. Oishi, T. Akiyama, M. Isobe, K. Ida, H. Nakano, A. Fujisawa, K. Nagaoka, M. Yoshinuma, Y. Yoshimura, K. Toi, S. Ohshima, M. Takeuchi, H. Iguchi, S. Nishimura, A. Shimizu, K. Matsuoka and C. Takahashi


Simultaneous Realization of High Density Edge Transport Barrier and Improved L-mode on CHS

Date of publication:

Oct. 2008

Key words:

21 IAEA Fusion Energy Conference, EX/P3-11


An edge transport barrier (ETB) formation and an improved L-mode (IL mode) have been simultaneously realized in high density region (bar{n}_e~ 1.2 x 1020m-3) on Compact Helical System (CHS). When the ETB is formed during the IL mode, the density reduction in the edge region is suppressed by the barrier formation. As a result of the continuous increasing of the temperature by the IL mode, the stored energy during the combined mode increased up to the maximum stored energy (W_p ~ 9.4kJ) recorded in CHS experiments. The plasma pressure in the peripheral region increases up to three times larger than that of the L-mode, and the large edge plasma pressure gradient is formed accompanying the pedestal structure. That is caused by the anomalous transport reduction that is confirmed from the sharp drop of the density fluctuation in the edge region. The neutral particle reduction in the peripheral region and the metallic impurity accumulation in the core plasma are simultaneously observed during the high density ETB formation.

List of NIFS Report (2008)Return toContents Page Return toNIFS Homepage