DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 402: | ||
| Name: | Yutaka Kamada ( |
Affiliation: | JAEA |
| Research Area: | ELM Control & Pedestal Physics | Presentation time: | Not requested | Co-Author(s): | A.Leonard, N.Oyama, H.Urano, Y. Sakamoto, M.Yoshida |
| Description: | By Utilizing the unique capability of rotation control with co- and counter- NBs in DIII-D and JT-60U and by utilizing the difference in the plasma shape and edge stability between the two tokamaks, we propose to conduct the inter-machine experiments on the rotation effects on the pedestal structure and type I ELMs. (ITPA Inter-machine experiment PEP-18) | ||
| Experimental Approach/Plan: | As the first step of the study, we propose the study on effects of rotation on Type I ELM, pedestal transport and core transport at different plasma shape. In JT-60U, effects of the toroidal rotation have been clarified at medium triangularity ~0.3. Based on the ITPA pedestal database, the pedestal structure in JT-60U and DIII-D are quite different: DIII-D has large pressure gradient and narrow pedestal width compared with JT-60U. This difference seems to be due to the plasma shape. In order to clarify the effects of rotation at different pedestal situation, we propose rotation scan experiments at higher triangularity in DIII-D and take the following data:
1) Frequency and energy loss (incl. ELM affected area) of type I ELMs, and Pedestal width and inter-ELM transport at the same _p-ped and q95 with JT-60U, 2) Frequency and energy loss of type I ELMs, and Pedestal width and inter-ELM transport at the same pedestal collisionality and q95 with JT-60U, and 3) Core thermal confinement of the plasmas in 1) and 2). By comparing the data in DIII-D and JT-60U, we can clarify whether the rotation effects are universal, and the dependence of these effects on plasma shape. | ||
| Background: | Recent tokamak experiments have revealed that the pedestal and core transport of the H-mode plasmas are determined under the linkage among pressure, current and rotation profiles. The goal of this research is to understand this complex system in order to improve predictive capability for ITER, and to develop control schemes for the pedestal parameters and ELMs and core transport. Concerning the parameter linkage, plasma rotation and its radial profile seem to play critical roles. Recent JT-60U experiment has demonstrated a shift of toroidal plasma rotation VT into co-direction reduces the inter-ELM transport loss and increase the pedestal height and width. In addition, type I ELM energy loss normalized to the pedestal stored energy (_WELM/Wped) increases with increasing co-directed rotation. The critical importance is to clarify the rotation effects on the pedestal structure and ELMs over a wide range of the plasma shape. Is is also important to separate the effects of rotation and ripple loss on the pedestal structure and ELMs. As for the core confinement of H-mode plasmas, both DIII-D and JT-60U have shown improved performance with co-directed rotation compared with counter rotation. The purpose of this study is to clarify the roles of plasma rotation systematically by utilizing the unique capability of rotation control with co- and counter- NBs in DIII-D and JT-60U and by utilizing the difference in the plasma shape and edge stability between the two tokamaks. | ||
| Resource Requirements: | TBD | ||
| Diagnostic Requirements: | Charge Exchange Recombination, Thomson etc.. | ||
| Analysis Requirements: | TBD | ||
| Other Requirements: | Joint Work with ' Rotation Phys.' group | ||
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