WEST Physics Basis

With WEST (Tungsten Environment in Steady State Tokamak) (Bucalossi et al 2014 Fusion Eng. Des. 89 907-12), the Tore Supra facility and team expertise (Dumont et al 2014 Plasma Phys. Control. Fusion 56 075020) is used to pave the way towards ITER divertor procurement and operation. It consists in implementing a divertor configuration and installing ITER-like actively cooled tungsten monoblocks in the Tore Supra tokamak, taking full benefit of its unique long-pulse capability. WEST is a user facility platform, open to all ITER partners. This paper describes the physics basis of WEST: the estimated heat flux on the divertor target, the planned heating schemes, the expected behaviour of the L-H threshold and of the pedestal and the potential W sources. A series of operating scenarios has been modelled, showing that ITER-relevant heat fluxes on the divertor can be achieved in WEST long pulse H-mode plasmas.EURATOM 63305

Plasma physics and control studies planned in JT-60SA for ITER and DEMO operations and risk mitigation

Lista completa de autores: Yoshida, M. ; Giruzzi, G.; Aiba, N.; Artaud, J. F.; Ayllon-Guerola, J.; Balbinot, L.; Beeke, O.; Belonohy, E.; Bettini, P.; Bin, W.; Bierwage, A.; Bolzonella, T.; Bonotto, M.; Boulbe, C.; Buermans, J.; Chernyshova, M.; Coda, S.; Coelho, R.; Davis, S.; Day, C.; De Tommasi, G.; Dibon, M.; Ejiri, A.; Falchetto, G.; Fassina, A.; Faugeras, B.; Figini, L.; Fukumoto, M.; Futatani, S.; Galazka, K.; García, J.; García-Muñoz, M.; Garzotti, L.; Giacomelli, L.; Giudicotti, L.; Hall, S.; Hayashi, N.; Hoa, C.; Honda, M.; Hoshino, K.; Iafrati, M.; Iantchenko, A.; Ide, S.; Iio, S.; Imazawa, R.; Inoue, S.; Isayama, A.; Joffrin, E.; Kamiya, K.; Ko, Y.; Kobayashi, M.; Kobayashi, T.; Kocsis, G.; Kovacsik, A.; Kurki-Suonio, T.; Lacroix, B.; Lang, P.; Lauber, P.; Louzguiti, A.; Luna, E. de la; Marchiori, G.; Mattei, M.; Matsuyama, A.; Mazzi, S.; Mele, A.; Michel, F.; Miyata, Y.; Morales, J.; Moreau, P.; Moro, A.; Nakano, T.; Nakata, M.; Narita, E.; Neu, R.; Nicollet, S.; Nocente, M.; Nowak, S.; Orsitto, F. P.; Ostuni, V.; Ohtani, Y.; Oyama, N.; Pasqualotto, R.; Pegourie, B.; Perelli, E.; Pigatto, L.; Piccinni, C.; Pironti, A.; Platania, P.; Ploeckl, B.; Ricci, D.; Roussel, P.; Rubino, G.; Sano, R.; Sarkimaki, K.; Shinohara, K.; Soare, S.; Sozzi, C.; Sumida, S.; Suzuki, T.; Suzuki, Y.; Szabolics, T.; Szepesi, T.; Takase, Y.; Takech, M.; Tamura, N.; Tanaka, K.; Tanaka, H.; Tardocchi, M.; Terakado, A.; Tojo, H.; Tokuzawa, T.; Torre, A.; Tsujii, N.; Tsutsui, H.; Ueda, Y.; Urano, H.; Valisa, M.; Vallar, M.; Vega, J.; Villone, F.; Wakatsuki, T.; Wauters, T.; Wischmeier, M.; Yamoto, S.; Zani, L.A large superconducting machine, JT-60SA has been constructed to provide major contributions to the ITER program and DEMO design. For the success of the ITER project and fusion reactor, understanding and development of plasma controllability in ITER and DEMO relevant higher beta regimes are essential. JT-60SA has focused the program on the plasma controllability for scenario development and risk mitigation in ITER as well as on investigating DEMO relevant regimes. This paper summarizes the high research priorities and strategy for the JT-60SA project. Recent works on simulation studies to prepare the plasma physics and control experiments are presented, such as plasma breakdown and equilibrium controls, hybrid and steady-state scenario development, and risk mitigation techniques. Contributions of JT-60SA to ITER and DEMO have been clarified through those studies.Comisión Europea - EURATOM 63305

Self-consistent simulation of plasma scenarios for ITER using a combination of 1.5D transport codes and free-boundary equilibrium codes

Self-consistent transport simulation of ITER scenarios is a very important tool for the exploration of the operational space and for scenario optimisation. It also provides an assessment of the compatibility of developed scenarios (which include fast transient events) with machine constraints, in particular with the poloidal field (PF) coil system, heating and current drive (H&CD), fuelling and particle and energy exhaust systems. This paper discusses results of predictive modelling of all reference ITER scenarios and variants using two suite of linked transport and equilibrium codes. The first suite consisting of the 1.5D core/2D SOL code JINTRAC [1] and the free boundary equilibrium evolution code CREATE-NL [2,3], was mainly used to simulate the inductive D-T reference Scenario-2 with fusion gain Q=10 and its variants in H, D and He (including ITER scenarios with reduced current and toroidal field). The second suite of codes was used mainly for the modelling of hybrid and steady state ITER scenarios. It combines the 1.5D core transport code CRONOS [4] and the free boundary equilibrium evolution code DINA-CH [5].Comment: 23 pages, 18 figure

Lower hybrid counter-current drive experiment in JET

12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France)Lower hybrid current drive has been demonstrated to be an efficient tool to modify the current profile in order to access to high energy confinement regimes. Counter-current drive could be an alternative scenario provided the current drive efficiency is not too small when fast electrons flow in the opposite way to the DC electric field. By reversing the toroidal field (Bt=-3.1T) and the plasma current (Ip=-1.45MA), counter current drive with lower hybrid waves has been investigated for the first time in JET. The experiments were carried out at low plasma density ( =1.0 x1019m-3 , ne(0)=1.6 x 1019m-3) with 2.9MW of lower hybrid power. The CRONOS code[1], which couples the diffusion equations to a 2-D equilibrium code, has been used to estimate the RF driven current. Runs indicate that loop voltage and internal inductance are best simulated with a current drive efficiency of –1.0 x 1019 A.W-1.m-2 with a peaked central LH power deposition deduced from DELPHINE[2]. This efficiency is indeed very close to the one found for co-LHCD at similar plasma current and density. Current profile evolves from a hollow profile (with a minimum at r/a ~0) and a maximum at r/a~0.4-0.5) to a rather flat profile (up to r/a=0.3)

Validation of equilibrium tools on the COMPASS tokamak

SOFT 2014 conference, submitted to Fusion Engineering and DesignInternational audienceVarious MHD (magnetohydrodynamic) equilibrium tools, some of which being recently developed or considerably updated, are used on the COMPASS tokamak at IPP Prague. MHD equilibrium is a fundamental property of the tokamak plasma, whose knowledge is required for many diagnostics and modelling tools. Proper benchmarking and validation of equilibrium tools is thus key for interpreting and planning tokamak experiments. We present here benchmarks and comparisons to experimental data of the EFIT++ reconstruction code [L.C. Appel et al., EPS 2006, P2.184], the free-boundary equilibrium code FREEBIE [J.-F. Artaud, S.H. Kim, EPS 2012, P4.023], and a rapid plasma boundary reconstruction code VacTH [B. Faugeras et al., PPCF 56, 114010 (2014)]. We demonstrate that FREEBIE can calculate the equilibrium and corresponding poloidal field (PF) coils currents consistently with EFIT++ reconstructions from experimental data. Both EFIT++ and VacTH can reconstruct equilibria generated by FREEBIE from synthetic, optionally noisy diagnostic data. Hence, VacTH is suitable for real-time control. Optimum reconstruction parameters are estimated

Physics and operation oriented activities in preparation of the JT-60SA tokamak exploitation

The JT-60SA tokamak, being built under the Broader Approach agreement jointly by Europe and Japan, is due to start operation in 2020 and is expected to give substantial contributions to both ITER and DEMO scenario optimisation. A broad set of preparation activities for an efficient start of the experiments on JT-60SA is being carried out, involving elaboration of the Research Plan, advanced modelling in various domains, feasibility and conception studies of diagnostics and other sub-systems in connection with the priorities of the scientific programme, development and validation of operation tools. The logic and coherence of this approach, as well as the most significant results of the main activities undertaken are presented and summarised.EURATOM 63305