PWI合同研究会筑波大学国際会議官, 2014.07.31国内国外直線・照射襲置研究の展開筑波大学プラズマ研究センター城本瑞鶴
Researches on plasma confinement devices such as tokamaks and stellarators are important to design and operate ITER and DEMO, since the topology of the magnetic field plays an important role and non-linear dependence between wall and plasma performance must be addressed.
M. Sakamoto, 2nd IAEA DEMO Workshop, Dec. 2013

ITER 100MW 10 MW/m² stationary 20 MW/m² (non-stationary) DEMO 500MW < 8 MVV/m² (SlimCS*)
M. Sakamoto, 2nd IAEA DEMO Workshop, Dec. 2013
▷Power handling has a direct impact on machine protection. Need to disperse the power ▷Particle handling relates to plasma performance. Need to concentrate the particles Compatibility of power and particle handling is crucial for steady state operation.
Photo: © EFDA-JET

A large step from now to ITER and DEMO
> New challenges for all issues related to fluence, neutron damage and wall temperature (last two will indirectly affect all others via material issues) May 23 rd, 2012 Institute of Energy and Climate Research – Plasma Physics | Association EURATOM – No 4
012) B. Unterberg

20th PSI (2012) B. Unterberg

ITER & DEMO Plasma Confinement Devices ) = V( O “Complementary studies” Contribution. Linear Plasma Devices Steady State Operation What is necessary? Extrapolation using simulation Fundamental study nnovation ew findings
Kanazawa Univ.: AMITP, AIT-PID NIT, Nagano college: CTP-HC Shinshu Univ.: no name Excellent researches on divertor simulation and PWI have been done in linear plasma devices by utilizing characteristics (uniqueness and innovative ideas) of each device Existing devices for example o PISCES-B: Beryllium o MAGNUM-PSI, PILOT-PSI: 。 . 。 o o High B field and transient heat load TPE: Tritium and radioactive material NAGDIS: W nanostructure, arcing etc. PS-DIBA: In situ measurement of dynamic & static retention TPD-SheetV: Sheet plasma, Omegatron mass Sprctrometer GAMMA 10/PDX: High ion temperature New Project 。 JULE-PSI (FZ-Juelich) 。 MPEX (ORNL) Japanese activity under NIFS bilateral collaboration o (Nagoya Univ., Tohoku Univ., etc.) Ref: N. Ohno, PMIF 2013
NAGDIS-II S. Takamura et al. PFR, Vol. 1 (2006) 051. http://www.jspf.or.jp/PFR/PDF/pfr2006_01-051.pdf Incident ion energy and W temperature are critical parameters for formation of nano- structure. E=50 eV, Ts=1400 K, He fluence: (a) 6 × 10²4 m−², (b) 1.1 × 10²5 m¯² (c) 1.8 × 10²5 m¯², (d) 2.4  ×  10²5 m¯² S. Kajita et al., Nucl. Fusion 49 (2009) 095005.
▷  W surface temperature decreased as nanostructure was formed on the surface. Total emissivity increased from 0.18 (non-damage) to 0.45-0.55 (nanostructure). ▷ The cooling comes mainly from an increase in the total emissivity of blackened tungsten. In addition, a deepening of floating potential due to suppression of secondary electron emission also contributes to such a temperature reduction. S. Takamura et al., JNM 438 (2013) S814. M. Sakamoto, 2nd IAEA DEMO Workshop, Dec. 2013
PISCES-A: L. Schmitz et al., JNM 176-177 (1990) 522. Plasma Detachment in the NAGDIS-II Device M. Sakamoto, 2nd IAEA DEMO Workshop, Dec. 2013
In the case of high density divertor plasma like DEMO (i.e. > 10²¹ m 3), the radiation transfer will play a significant role, since the plasma will be optically thick. The mean free path for Lα photons can be shorter than 0.2 mm. Effective ionization rate coefficient will be increased and radiation cooling will be reduced. Small uncertainty of prediction of P rad leads to large effect on target heat Fundamental study using a linear plasma device is important for validation of the model and getting an accurate database, since the plasma is well defined. Process of decreasing in electron and ion temperatures in SOL & divertor region and  effect of transient plasma event like ELM are important to study the divertor detachment.
小特集|DEMOに向けた直線型装置を用いた境界プラズマ,プラズマ・壁相互作用研究1.直線型プラズマ生成装置の現状とDEMOのダイバータ設計における課題小特集 DEMOに向けた直線型装置を用いた境界プラズマ,プラズマ・壁相互作用研究ダイバータにおける熱流制御とプラズマ材料相互作用」。小特集 DEMOに向けた直線型装置を用いた境界プラズマ,プラズマ・壁相互作用研究3．直線型プラズマ生成装置を用いたプラズマ・壁相互作用研究小特集 DEMOに向けた直線型装置を用いた境界プラズマ,プラズマ・壁相互作用研究4.まとめにかえて坂本瑞樹、大野哲靖、朝倉伸琴、星野一生菊池祐介、澤田圭司、高村秀一上田良夫、永田正義波多野雄治、宮本光貴、島田雅、上田良夫、時谷政行中県洋町
International Research Center for Nuclear Material Science (IRCNMS), Institute for Materials, Tohoku Univ. has a long history to conduct neutron irradiation tests using nuclear reactors overseas (BR2) as well as in Japan (JMTR, JOYO, JRR-3) → Many neutron-irradiated samples already exist in IRCNMS A compact divertor simulator with a TDS device is constructing in Nagoya Univ (Prof. Ohno).
Tokai Univ.: TPD-SheetV Kanazawa Univ.: AMITP, AIT-PID NIT, Nagano college: CTP-HC Shinshu Univ.: no name