Presented by Y. Kamada

Large Tokamak Meeting 28-29 June 2006

JT-60U contribution to ITPA/IEA inter-machine experiments and related study for ITPA/IEA

2005-2006 Contributions

Joint Experiment CDB-2: degradation JT-60U experiment, Urano et al., NF Bth ~ -0.6

Analysis of JT-60U data and ITPA DB, Takizuka et al., PPCF (Takizuka, 9th & 10th TG meetings)

Particle Transport WG Density peaking in JT-60U (low *?) (Takenaga, 9th meeting)

Profile DB : JT-60U data update & new submission

Modeling Integrated modeling (Fukuyama, Takizuka, 10th meeting)

1-1 Confinement Database and Modeling TG : results

Joint Experiment CDB-9: Density profiles Experiments in JT-60U planned for 2006 (Takenaga)

Experiments and analysis Effects of ripple, rotation, shaping, fuelling Density limit (nGW) (Yamada-Takenaga)

Database H-mode DB : JT-60U degradation

hybrid/improved H-mode (to be discussed) Threshold DB : JFT-2M, CHS

Modeling Integrated modeling ITER simulation (Fukuyama, Hayashi with SS TG)

1-2. Confinement Database and Modeling : plan

1. Inter-Machine Experiments on JT-60U1-1. Steady-state plasma development(TP-1) In a strong reversed shear plasma, fBS~70% was maintained for 8 s. 1-2. Hybrid regime development (TP-2) The duration of high beta sustainment with high confinement has been extended with reduction of toroidal field ripple; N = 2.5 with HH98y2 ~1.1 was maintained for 17.6 s and N = 2.3 with HH98y2 ~0.9 for 28.6 s. 1-3. Other experiments In the experiments on ITB degradation with ECRF electron heating (TP-3) in weak positive shear plasmas, it was found that the degradation effect depended on the plasma current, less effective at a higher current. In spontaneous toroidal rotation study (TP-6.1), toroidal rotation profile data in EC+LH ITB plasmas have been provided for an IAEA by J. Rice, and change in the toroidal rotation after ripple reduction with ferritic steel inserts has been reported.

2-1. Results on Transport Physics

1. Inter-Machine Experiments on JT-60U　 1-1. Steady-state plasma development / Hybrid regime development Current profile control in a weak shear regime will be attempted 　 by using LHCD. 　 1-2. Other experiments Toroidal rotation profile data in ECH H-mode plasmas will be 　 provided for TP-6.1.

2. Database Profile and scalar data of advanced scenario plasmas in JT-60U 　 will be submitted according to requests from the TG.

2-2 . Transport Physics: plan

3. Pedestal and Edge Physics 1. Inter-machine exp. 1-1: ripple effects JT60U/JET (PEP-1&3): 2006 Jun. (done) 1-2: Grassy ELM regime identification: JT60U/AUG/JET (PEP-13, PEP-17): 2006 Sep. (plan) 1-3: QH comparison : JT60U/DIIID (PEP-14): 2006 Jun.(done)

2. Data supply for TG works 2-1: scalar data of pedestal in AT plasmas 2-2: profile data for modeling studies

3. Detailed profile evolution measurement of pedestal and SOL ; at ELM and inter-ELM with new diagnostics (fast CXRS, modulation CXRS, BES, Ha camera etc)4. Unification of effects of rotation5. Expansion of grassy ELM regime

7. Integrated model of Pedestal / ELM / SOL-divertor

1~6: JT-60U

1. Inter-Machine Experiments on JT-60U 1-1. Steady-state plasma development (SSO-1)

•High fBS (>70%) RS discharges will be optimized (quasi-SS, overdrive (fBS >100% ), weaker shear).•Study response and controllability in these high fBS plasmas.• Improve weak shear steady-state candidate discharge (quasi-SS, shear optimization, j(r) control).• Investigate beta-limit in both weak and reversed shear plasmas.

1-2. Hybrid regime development (SSO-2)•Operational space in (ne, q95, Ip, *) will be extended with higher heating power available in reduced toroidal field ripple.•Document MHD effect, * dependence on q(r), transport, stability.

1-3. Others•Develop real time j(r) control in advanced plasmas. (SSO-3)• Investigate edge pedestal in advanced plasmas. (SSO-4)

4-2. Steady-state Operation: plan

1. Inter-Machine Experiments on JT-60U1-1. Steady-state plasma development (SSO-1)　 - High fBS of >~70% was maintained in an RS plasma. q(r) was almost 　　 unchanged for ~3s.　 - In a high fBS RS discharge, q(r) was flattened by ECCD.　 - Even higher fBS (~100%) has been studied. - Sustainment of Ip(~0.5MA) for ~2s without flux input nor external CD was demonstrated.　 - Response and controllability in these high fBS plasmas have been studied.　 - Investigate beta-limit in both weak and reversed shear plasmas.1-2. Hybrid regime development (SSO-2)　 - High N (=2.3) was maintained for ~28.6s with good confinement (H98(y,2)>1).　 - High N·H98(y,2) (>~0.2) was maintained as well. Almost in the ITER Hybrid regime.　 - Impact of ECRF to weak shear Ti ITB has been investigated.1-3. Other　 Real time j(r) control has been applied on higher N plasmas. (SSO-3)　 Investigate edge pedestal in advanced plasmas. (SSO-4)

4-1. SSO TG activities: results

1. RWM • Identify the RWM, and measure the mode structure, growth and damping rates an

d frequency • Clarify the effect of the rotation on RWM in high beta experiments2. NTM • Demonstration of stabilization of m/n=2/1 NTM with ECCD • Identify contributions of each terms of the modified Rutherford equation • Control of m/n=3/2 NTM by central co-ECCD • Database of the onset of NTM for steady state plasma without sawtooth3. Disruption • Provide database of fast current quench time of reversed shear plasmas in JT-60U • Production, loss and control of the post-disruption runaway electrons by external a

ctuator • Mitigation of the disruption of the low beta reversed shear plasma, and sustainme

nt of reversed shear plasma for the long pulse4. Energetic particles • Stability of AEs, and transport of high energy particle due to AEs • Measurement of intermediate-n AEs • Effects of high energy particle confinement by the insertion of ferritic steel

5. MHD, Disruption and Control

６ . PWI and SOL/divertor

1. Plasma Wall Interaction Research (Experiments & Material analysis) 1-1) Local gas puff at the outer divertor: • 2nd 13C tracer experiment for C-flow and deposition studies • Evaluation of photon efficiency for multi-C gas (C2D6, C3D8 ) 1-2) C-deposition analysis for the first wall tiles as well as divetor 1-3) Erosion&deposition and transport of Fe&Cr from Ferritic steal tile. 1-4) Extension of W erosion and deposition in divertor. also contributions to DSOL-2,9,13

2. SOL and Divertor Plasma Physics 2-1) Wall saturation process study at high D-flux in long pulse (35s). 2-2) SOL fluctuation study for intermittent radial transport, using Fast TV camera and Mach Probes at midplane, X-point & inner SOL. 2-3) ELM propagation is studied by probes and fast TV camera: 2-4) 2nd SOL effects on SOL and edge is studied at high . 2-5) Recombination/MAR and Carbon transport in the detach divertor are si

multaneously studied with new spectrometer system (2D array tomography of most D & C lines) and Monte-Carlo simulation.

2-6) Metal(W&Fe) transport in edge/core is prepared, using IMPACT-code.

7. Diagnostics Alpha particle diagnostics (CO2 laser CTS, He beam & double CX, m

ulti-foil / scintillator lost alpha detector , -ray spectroscopy, etc.) First mirror damage against helium irradiation Radiation effects on diagnostics components Neutron diagnostics (spectrometer, CVD Diamond Detector, microfi

ssion chamber, liquid activation system, parallel plate avalanche counter, etc.)

Thomson scattering system (new YAG ceramics, Fourier spectrometer, etc.)

Toroidal / Poloidal FIR laser polarimeter / interferometer Divertor Spectroscopy (Impurity influx monitor, etc.) Imaging Diagnostics (Bolometer, ECE, Reflectometer) Advanced plasma control (j(r), NTM, etc.) Analysis of neutronics and electromagnetic force for port plug

design

JA contribution to ITPA: 2006 -2007 plan