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林 伸彦; 本多 充; 白石 淳也; 宮田 良明; 若月 琢馬; 星野 一生; 藤間 光徳; 鈴木 隆博; 浦野 創; 清水 勝宏; et al.
Europhysics Conference Abstracts (Internet), 39E, p.P5.145_1 - P5.145_4, 2015/06
Towards prediction and control of JT-60SA plasmas, we are developing codes/models which can describe physics/engineering factors, and integrating them to one code TOPICS. Physics modelling: Coupling with MINERVA/RWMaC code showed that MHD equilibrium variation by centrifugal force largely affects RWM stability and the toroidal rotation shear stabilizes RWM. Coupling with OFMC code for NB torques, 3D MHD equilibrium code VMEC and drift-kinetic code FORTEC-3D for NTV torque, and toroidal momentum boundary model, predicted the core rotation of 
2% of Alfv
n speed for a ITER hydrogen L-mode plasma. Coupling with core impurity transport code IMPACT showed the accumulation of Ar seeded to reduce the divertor heat load is so mild that plasma performance can be recovered by additional heating in JT-60SA steady-state (SS) scenario. Simulations coupled with MARG2D code showed that plasma current can be ramped-up to reach 
3 with MHD modes stabilized by ideal wall and with no additional flux consumption of central solenoid in JT-60SA. Engineering modelling: Coupling with integrated real-time controller showed that simultaneous control of 
and 
is possible at 4 in JT-60SA SS scenarios. MHD equilibrium control simulator MECS demonstrated equilibrium control during heating phase and collapse induced events within power supply capability of PF coils in JT-60SA.
浦野 創; 相羽 信行; 神谷 健作; 鎌田 裕; JT-60チーム
Europhysics Conference Abstracts (Internet), 39E, p.P5.146_1 - P5.146_4, 2015/06
トカマクにおける周辺ペデスタル構造は炉心プラズマ全体の閉じ込めや核融合炉の出力に対する境界条件となるため適切な予測とその制御が求められる。これまでに周辺プラズマにおける無次元量による周辺ペデスタル幅の定量化が行われてきており、周辺ペデスタル幅は規格化ポロイダルベータ値の平方根に比例することが知られている。しかし、この無次元量による評価は衝突周波数やプラズマ形状を固定した実験下で行われているため、特に衝突周波数による効果は未だよく分かっていなかった。そこで本研究ではJT-60Uにおいて衝突周波数スキャン実験を実施し、周辺ペデスタル幅の衝突周波数依存性を調べた。衝突周波数を0.04から0.2まで変化させたところ、peeling-ballooningモードで発生したELM周波数の増大及びELMエネルギーパルスの低下が観測された一方で、周辺ペデスタル幅に大きな差異が見られなかった。しかし、さらに衝突周波数を上げた実験では、周辺ペデスタル幅の増大が観測されており、これはinfinite-n ballooningモードでELMが発生しており、MHD不安定性の発生領域がペデスタル構造に寄与しているという重要な知見を得た。
若月 琢馬; 鈴木 隆博; 林 伸彦; 白石 淳也; 井手 俊介; 高瀬 雄一*
Europhysics Conference Abstracts (Internet), 39E, p.P5.144_1 - P5.144_4, 2015/06
We have investigated reduction of the CS flux required in the plasma current ramp-up phase using non-inductive current drive in JT-60SA with an integrated modeling code suite (TOPICS). JT-60SA will be equipped with various types of neutral beams different in the beam trajectories and energies (85 keV and 500 keV). We have made a scenario in which the plasma current is ramped up from 0.6 MA to 2.1 MA in 150 s with no additional CS flux consumption by overdriving the plasma current (
, 
: non-inductively driven current and 
: plasma current) with neutral-beam-driven and bootstrap current. In order to achieve the current overdrive condition from 0.6 MA, the current drive by the lower energy neutral beam injection (85 keV) is effective. The higher energy neutral beam injection (500 keV) cannot be utilized in this early phase with a low plasma density due to a large shine through loss, while it can effectively be utilized in the later phase. We have also investigated ideal MHD instabilities using a linear ideal MHD stability analysis code (MARG2D). External kink modes can be stabilized in most of the time during the current ramp-up if there is a perfect conducting wall.
菊池 満; Medvedev, S.*; 滝塚 知典*; Fasoli, A.*; Wu, Y.*; Diamond, P. H.*; Duan, X.*; 岸本 泰明*; 花田 和明*; 他41名*
Europhysics Conference Abstracts (Internet), 39E, p.P4.179_1 - P4.179_4, 2015/06
核融合炉における熱粒子制御は挑戦的課題である。定常的な熱負荷とエルムによる過渡的熱負荷を緩和する新しい方策として負三角度トカマクを評価している。これまで、負三角度は磁気丘であるにもかかわらず、ダブルヌルでは炉に使えるレベルの規格化ベータ値3以上が安定であることを見いだしている。本論文では、シングルヌル平衡配位とその理想電磁流体安定性を報告する。
本多 充; 福山 淳*
no journal, ,
The one-dimensional multi-fluid transport code TASK/TX has been developed for investigating the physics in tokamaks regarding rotation, the radial electric field 
, transient phenomena and so on. Compared to diffusive transport equations, its equation system is more fundamental in that it is based on the so-called two-fluid equation system that consists of the equations of motion together with Maxwell's equations. For example, in TASK/TX, an explicit quasi-neutrality condition is not thus required. Highly consistency of the system enables us to reproduce the 
torque and the concomitant generation of by itself. TASK/TX has originally built on the cylindrical coordinates for the sake of simplicity and thus no geometrical factors enter. The original set of equations is sufficient to qualitatively investigate the physics, but it is hardly applied to actual tokamak plasmas due to their shaping. From the physics point of view, the Pfirsch-Schl
ter enhancement of the dielectric constant of a plasma cannot be expressed, for example. Recently we have derived the set of governing equations on the tokamak flux coordinates in a manner consistent with the current TASK/TX concept. The set of equations are renewed to be more suited to the actual numerical implementation and are implemented in TASK/TX. Coupling of TASK/TX and an equilibrium solver makes it possible to carry out time-dependent simulations in actual tokamaks.
