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The progress in the J-TEXT tokamak. Ge Zhuang, Kenneth Gentle, Zhijiang Wang , Yonghua Ding, Ming Zhang, J-TEXT team. Huazhong University of Science and Technology. 6th US-PRC Magnetic Fusion Collaboration Workshop July 11, 2012. Outline. Hardware development on J-TEXT
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The progress in the J-TEXT tokamak Ge Zhuang, Kenneth Gentle, Zhijiang Wang, Yonghua Ding, Ming Zhang, J-TEXT team Huazhong University of Science and Technology 6th US-PRC Magnetic Fusion Collaboration Workshop July 11, 2012
Outline Hardware development on J-TEXT New diagnostics systems on J-TEXT Research progress on J-TEXT Collaboration and future plan
Reconstruction of SRMP coil Mode structure of SRMP @ r=a=0.27m (Gs/kA) A typical current wave of SRMP coil Layout of SRMP (Static Resonant Magnetic Perturbation ) coil • Reconstructed the original SFX (Stochastic Field Experiment) coil of TEXT-U (now named as SRMP coil on J-TEXT). • 3 cosine coils and 2 sine coils. • Resonant perturbation modes: m/n=2/1 (up to 0.64 GS/kA) and 3/1 (up to 0.8 GS/kA) 4000A
Dynamic Resonant Magnetic Perturbation coils 2/1,2.59Gs/kA Mode spectrum Layout of DRMP coils Spatial phase of 2/1 mode • Consists of 12 saddle in-vessel coils; • Produce rotating m/n=2/1 dominated perturbation to study its effects on tearing mode and edge parameters; • 2.59Gs/kA at r=a(0.27m).
Upgrade the flywheel motor-generator 50Hz(CN) 591RMP Rotation 60Hz(US) 713RMP Dual-feed speed control system Simulation result Rotation Prototype result
Power supply R&D for Divertor coils Divertor coils Bias coils Vacuum vessel TF coil innel bore
Installation of graphite Wall • Graphite tiles cover most of the inner wall of J-TEXT • A new differential pumping system for residual gas analyzer(RGA) for on-line monitoring the impurity composition
New look of the J-TEXT tokamak A snapshot of J-TEXT Layout of J-TEXT systems
Improve performance of the J-TEXT tokamak Shot:1023914
Outline Hardware development on J-TEXT New diagnostics systems on J-TEXT Research progress on J-TEXT Collaboration and future plan
3-wave polarimeter-interferometer 3-D scheme of J-TEXT polarimeter • Simultaneous FA (Faraday angle)and density measurement • High resolution • Capable for fluctuation measurement • Collaborated with UCLA
Table optics Optical tower
Experimental results • Phase resolution • FA: <0.1 degree • Density: <0.5 degree (~5x1015m-2 ) • Temporal resolution • 1μs • Spatial resolution • 1.5 cm min.
X-ray Imaging Crystal Spectrometer • Spherically bent crystal • Heliumlike argon: 3.9494Å~3.9944Å • Lattice space: 2d=4.913Å • Curvature: 3.823m Side-view of XICS on J-TEXT Ionization state distribution of Argon Optical principle of XICS
Schematic Layout of XICS • Detectable region: -10cm ~ 10cm (ver) • Spatial resolution: 3.15cm • Spectra resolution: λ/Δλ=8600 Top view of XICS Side-view of XICS
2-segmented Multi-wire proportional counter (MWPC) • Data acquisition: X1, X2, Y1, Y2, Anode • Delay line Constant fraction time-discriminator • External cable delay of 8ns • Time-to-amplitude-to-digital convertor (ATDC) • Transfer to PC through USB interface
Outline Hardware development on J-TEXT New diagnostics systems on J-TEXT Research progress on J-TEXT Collaboration and future plan
Magnetic perturbations MHD model for mode locking and experiments Reduced MHD model • In order to study the instabilities MHD related, reduced MHD model (Ohm’s law, the equation of motion and energy conservation) are utilized. Recently, mode locking by error field, nonlinear evolution of tearing modes and their interaction with RMPs are studied. Theoretical model
Numerical modeling • Three regimes have been found: • Mode suppression regime, • ψa<4.5×10-5aBt • Small locked island regime • 4.5×10-5aBt<ψa<5.9×10-5aBt • (iii) mode locking regime • ψa>5.9×10-5aBt
Influence of RMP on MHD activities Experimental results Numerical modeling Ip=180kA, Bt=1.74T, qa=3.5 RMP: 0.637G/kA, Icoil=5kA(flattop) Mirnov >50, frequency 30, W2/1 30 a=8.510-5bra=mBta=3.1G Icoil=4.87kA
Influence of RMP on MHD activities(2) Experimental results Numerical modeling Ip=180kA, Bt=1.74T, qa=3.5 RMP: 0.637G/kA Icoil=6kA(flattop) Mode locking
Runaway current statistics qa=3.82 qa=3.47 Long live runaway current plateau • The threshold of runaway current generation is Bt>2.1T, Ip<220kA in J-TEXT • The disruptions were triggered by intensive gas puffing at 0.15s
Lost of displacement control Suppression of runaway generation by intensive gas puffing. The runaways are well confined during current quench phase as indicated by the HXR flux.
Outline Hardware development on J-TEXT New diagnostics systems on J-TEXT Research progress on J-TEXT Collaboration and future plan
Collaboration on J-TEXT (UT @Austin) • improve the performance of the JTEXT operation • install Ergodic Magnetic Limiter, ECE system, and movable probe diagnostic system • upgrade JTEXT to a divertor machine • conduct impurity transport experiments • advance disruption studies • particle transport when the plasma approaching density limit • edge turbulence such as asymmetries and coherent structures
Collaboration on J-TEXT (UCLA) • David Brower and W.X.Ding(UCLA) visited HUST to collaborate on advanced polarimeter—interferometer system on J-TEXT. • Development of high resolution polarimetry-interferometry diagnostic for J-TEXT tokamak • Participation in joint experiments relevant to J-TEXT polarimetry–interferometry
David Hwuang (UCDAVIS,PPPL,Sandia,HyperV) collaborated HUST on runaway electron mitigation on J-TEXT • The layout and parameters of JCT injector on J-TEXT is finished • The experimental studies of runaway electron mitigation effects with JCT will be carried when the system is set up
Collaboration on J-TEXT (PPPL) • L. Zakharov(PPPL)visited HUST for Disruption Studies on J-TEXT • Some numerical simulations have been done • The experimental studies of currents in conductive shells will be conducted on J-TEXT after some modifications on the inner wall of the machine HUST wish to build up more collaboration in fusion science and technology between China and the United States
J-TEXT Two Year Plan Systems to be installed • 1.2MW/60GHz ECRH system for plasma heating and current drive • Diagnostic NBI for ion temperature measurement Research topic • Plasma disruption and mitigation • Particle transport • Edge plasma physics • Rotating RMP interaction with plasma
Important Notes: The J-TEXT tokamak can operate for more than 6 months per year (April, May, June, October, November, December, perhaps March and January) Proposals for use of the J-TEXT tokamak can be submitted to Ge Zhuang(ge-zhuang@mail.hust.edu.cn) or prof. Kenneth Gentle(k.gentle@mail.utexas.edu)