Overview of Magnetic Fusion Simulation in China J. Q. Dong Southwestern Institute of Physics China The Workshop on ITER Simulation May 15-19, 2006, Beijing, China
Outline 1, Introduction 2, Confinement 3, Stability 4, Divertor and Edge Physics 5, Wave Heating, Current Drive and Fuelling 6, Others 7, Summary
1, IntroductionA, Institutions and universities • Southwestern Institute of Physics (SWIP), Chengdu • Institute of Plasma Physics (IPP), Hefei • University of Science and Technology of China (USTC), Hefei • Tsinghua University (THU), Beijing • Dalian University of Technology (DUT), Dalian • Huazhong University of Science and Technology (HUST), Wuhan • Institute of Physics (IP), Beijing • PKU, ZJU, NKU & NHU
B, Devices • HT-7 (IPP) • SUNIST (THU) • HL-2A (SWIP) • EAST (IPP) • J-TEXT (HUST)
SUNIST SUNIST device SUNIST main parameters: major radius R 0.3m minor radius a 0.23m Aspect ratio A ~1.3 elongation κ ~1.6 toroidal field （R0） BT 0.15T plasma current IP 0.05MA central rod current of BT IROD 0.225MA flux (double swing) ΔΦ 0.06Vs
HL-2A R=1.65 m, a=40 cm, Ip=350 kA, Bt=2.5 T, td=2s
J-TEXT • From TEXT-upgrade, FRC, U-Texas • R=1 m, a=26 cm, Ip=300 kA, Bt=2.5 T
C, Present Status of magnetic fusion simulation • With a small scale, mainly at IPP and SWIP • At a starting stage, 1) more universities are eager to participate 2) the big experiment program has to be supported by theory and simulation
2, Confinement Works onMHD Equilibrium • Theory of tokamak equilibria with central current density reversal (Wang, PRL, 2004) • Analytic description of high poloidal beta equilibrium with a natural inboard poloidal field null (Shi, PoP, 2005) • Tokamak MHD equilibria with toroidal flow or sustained by high fraction bootstrap current (Ren, PST, 2006 and Shi, CPL, 2003)
2.1.MHD equilibrium (1) • MHD equilibrium configurations of EAST were simulated with the EFIT code.
10135020重点基金结题 t=0.584 s t=1.29 s t=0 t=1.99 s t=4.11 s
2.1.MHD equilibrium (2) • the HL-2A equilibrium configurations calculation with the SWEQU code
2.2. Micro-instabilities and turbulence (1) • Electrostatic and electromagnetic micro-instabilities (ITG, ETG, TEM, AITG, SWITG, SWETG) are studied with fluid and kinetic theories • Formation of large-scale structures in (ETG) turbulence: zonal flows or streamers, and the role of magnetic shear in the formation dynamics are numerically demonstrated.
Magnetic shear governs spectral anisotropy of ETG; Structure selection of zonal flows or streamers streamer dominated Zonal flow dominated Homogeneous ETG Micro-instability and turbulence (4)Formation of large-scale structures Modulation instability analysis show: Structure selection depends on spectral anisotropy of ETG fluctuations Zonal flow-like bump Streamers Zonal flow Streamer-like bump
2.3. Predictive transport modeling (1) • Reversed shear configuration formation on EAST
2.3. Predictive transport modeling(2) • Quasi-stationary RS operation establishment with current profile control on HL-2A • Development of double transport barrier in shaped plasmas of HL-2A
Fig.1.1 Waveforms of the plasma current Ip, loop voltage Vp, the NBI power PNB, and the LH wave power PLH Fig.1.2 Magnetic geometry of the discharge
Fig.1.3 (a) The temporal evolution of LH wave driven current profile, and (b) q profiles at different times for the sustained RS discharge
The double transport barrier is indicated by two abrupt decreases of the ion heat diffusivity, of which the two minima are located near the shear reversal point, min 0.55, and near the plasma edge, 0.95, respectively. The elevated heat diffusivity between the two minima separates the two barriers. Fig.2.3 Profiles of q and ion heat diffusivity, i (at t=1.0s) for the elongated D-shape plasma.
2.4.Analysis of plasma relaxed statesfor inductively driven tokamaks of arbitrary aspect ratio • A variety of current profilesobserved in tokamak experiments are reproduced theoreticallyformprinciple of minimumdissipation rate subject to helicity and energy balance.(Zhang) 2.5. New Coulomb logarithm and its effects • New Coulomb logarithm and its effects on the Fokker-Plank equation, relaxation time and cross field transport (Li)
3, Macro-instabilities 3.1.Vertical displacement instability analysisof EAST
3.2. Resistive TM and flow layer formation( ) Evolution of magnetic island width and amplitude of velocity shear
Profiles of velocity shear • Assuming we estimated • This is comparable with the turbulence suppression shearing rate
3.3. Fast particle MHD • Destabilization of internal kink modes at high frequency by energetic circulating ions (Wang, PRL 2001) • Sawtooth stabilization by barely trapped energetic electrons (Wang, PRL 2002) • Fish bone instability driven by energetic electrons (Wang, Z.T., PST, 2005 )
4, Divertor and Edge Physics • EAST SOL/Divertor physics analysis (Zhu) • HL-2A SOL/Divertor physics analysis (Pan) • Atomic and molecular physics:The neutral transport modeling was performed for the HT-7 hydrogen removal experiment with DEGAS2 code .
5, Heating, Current Drive and Fuelling 5.1.ECRH and LHCD,Fokker-Planck study of tokamak ECRH & LHCD were performed for the HL-2A tokamak discharges (Shi & Jiao) 5.2.Ion cyclotron resonance heating (ICRH) (Ding) 5.3.Synergetic simulation of LHW and IBW/ICRF (Ding) 5.4. Penetration and deposition of a supersonic molecular beam in the HL-1M tokamak: The supersonic molecular beam (SMB) ablation and penetration processes in HL-1M tokamak experiments were studied(Jiao, PPCF, 2003) 5.5. Neutral beam relaxation analysis
6,Others • Simulation of collisionless shock wave with ideal MHD equations (Yang)
7, Summary 7.1. Code development and import 1) MHD equilibrium codesSWEQU&TOQ 2) MHD equilibrium reconstruction codeEFIT 3) Gyro-fluid code for ETG turbulence studies in a slab 4)Linear PIC codeTPICfor ETG & ITG in a torus 5)Integral eigenvalue codeHD7for ETG, TEM & ITG in a torus 6)Integral eigenvalue codeHD7slabfor ETG & ITG in high βplasmas of slab
7) FOKKER-PLANK codes RFP &FPPCRAYwith&without relativistic effects 8) CodeLSCfor LHCD 9)Resistive (viscosity) MHD codeDMHD 10)Ideal MHD instability codesGATO&BALLO 11) Edge physics simulation codeSOLPS (B2.5+ EIRENE) 12) Plasma surface interaction codes PSIC & DEGAS2 13)Transport codeTRANSP 14) MHD shock wave simulation code
7.2. Important topics not touched 1) Resistive wall mode (RWM) & edge localized mode (ELM) 2) Toroidicity induced Alfven eigen-mode (TAE) 3) Ideal and resistive ballooning mode; 4) Nonlinear wave-plasma interactions 5) Kinetic simulation of turbulence and transport 7.3. Fields have to be emphasized in the future • Integrated modeling of tokamak discharges • Simulation of nonlinear processes in tokamak plasmas
7.4. Suggestions • Enhancing the existing programs • Establishing new institutes for fusion theory and simulation & encouraging participation of universities • Establishing a national program • Dividing efforts to two fields: advanced plasma physics (turbulence & transport, MHD, coherent structure formation, wave plasma interaction, energetic particle physics and edge physics …) and tokamak modeling (modules & integrated simulations for experiments: HL-2A, EAST and ITER)