Real-time magnetic equilibria for NTM stabilisation on AUG

Transcription

1 Real-time magnetic equilibria for NTM stabilisation on AUG JANET : Just ANother Equilibrium code for Tokamaks L.Giannone, A.Bock, R.Fischer, J.C.Fuchs, K.Lackner, M.Maraschek, P.J.McCarthy, Y.Podoba, R.Preuss, M.Reich, A,Scarabosio, W.Schneider, K.H.Schuhbeck, J.Stober, W.Treutterer and AUG Team Q.Ruan, L.Wenzel (NI) R.Cole, M.Fitzek, K.Lueddecke (UCS)

2 Magnetic flux sensors Real-time digital control of plasma position and shape on the TEXTOR tokamak Ph.D Thesis, 2009, M.Mitri PXI BUS (PCI for instrumentation) Controller Real-time target FPGA based input/output cards 132 MB/s, 33 Mhz, 32 bit DAQ cards

3 Calibration and optimisation Channels Magnetic filed (T) Time (s) No optimisation 50 Bthe14 Bthe16 Bthe18 Bthe20 Bthe22 Bthe24 Bthe26 Bthe28 CalcDiff Difference (T) Text Flux loop position, gains and coil current optimised Time (s) 38 Bthe14 Bthe16 Bthe18 Bthe20 Bthe22 Bthe24 Bthe26 Bthe28 + poloidal field coil position and probe position/angle Histogram Graph histogram count Histogram Graph histogram count Histogram Graph 274 histogram count count ,05 0 0,05 amplitude (T) 0,1 count ,005 0 amplitude 0,005 count ,005 0 amplitude (T) (T) Q.Ruan, L.Wenzel - steepest descent algorithm 0,005

4 AUG DAQ and Control The LabVIEW RT and Solaris plasma diagnostics communicate with the VxWorks/Linux control system using XML files in the non-real time phase and UDP or VMIC reflective memory in the real time phase Magnetic (FP+GS) TORBEAM VMIC Control System UDP Send ψ(r,z) [39x69] by reflective memory (VMIC PCIe 5565 PIORC : 170MB/s) < 1 ms latency for NTM control experiments Bolometer Manometer Halo Current Loop Voltage ICRH In-line ECE MP coil current MSE DCN ECE

5 RT Grad-Shafranov solver Solve GS equation for magnetic equilibrium of tokamak Data Acquisition Constrained by 40 probe measurements Actuators Control Magnetic Equilibrium and 18 Dpsi measurements = ψ 1 - ψ 2 Slow loop equilibrium calculation takes 0.49 ms(4) for 33x65 grid using LabVIEW RT 2011 on 2xquad-core 3.46 GHz Intel Xeon > fast enough for soft control problems on AUG (e.g. NTM control) FPP - two times slower - integration of MSE would need testing

6 rtefit algorithm g1 Current basis functions g4 A x g1 A x g4 F1 F4 Response matrix Σ Weighted sum a[4] g solver rtefit Find set of coefficients for current profile basis functions giving best fit to probe measurements. One solver iteration using flux surfaces from previous time step is sufficiently accurate. Ψ Measurements LS Fit Real time equilibrium reconstruction for tokamak discharge control J.R.Ferron, M.L.Walker, L.L.Lao, H.E. St. John, D.A.Humphreys, J.A.Leuer Nuclear Fusion, 38, 1055, 1998

7 Real-time GS + DAQ Fast Loop ( ms) DAQ Vacuum field correction of probe measurements Function parameterisation ( + ISOFLUX ) RTFIFO out probe measurements coil currents Thread 1 Thread 2 Slow Loop (3 ms) RTFIFO in probe measurements Rc,Zc Contour integrals for q,s1,s2 -> βp li RT Grad-Shafranov solver ( fit probes only ) RTFIFO out ρ(m/n) ρ(ece) RTFIFO out ψ(r,z) Thread 1 Thread 2 MSE Loop (3-6 ms) RTFIFO in probe measurements coil currents MSE Contour integrals for q,s1,s2 -> βp li RT Grad-Shafranov solver ( fit probes + MSE ) RTFIFO out ρ(m/n) ρ(ece) RTFIFO out ψ(r,z) Thread 1 Thread 2

8 JANET dataflow

9 RT GS algorithm CLISTE uses double cyclic reduction (K.Lackner) EFIT uses cyclic reduction/tridiagonal solver (H.St. John) g(r,z) Ψ1 idst Ψ Ψ2 Fast Solver BC=0 BC Fast Solver g(r,z)=0 A x vec

10 Q.Ruan, L.Wenzel (NI Big Physics Scientific Computing) - reconstruct only necessary elements in first step - single thread solution only RT GS first solver step M.H.Hughes, Solution of Poisson's equation in cylindrical coordinates Computer Physics Communications, Volume 2, Issue 3, p , Preuss/Hallatschek g(r,z) DST Tridiagonal Solver idst edge ψ edge BC BC=0 Save some idst

11 RT GS second solver step g(r,z) = 0 BC Special DST Tridiagonal Solver From first step + idst Save 50% of DST/iDST Ψ Q.Ruan, L.Wenzel - special DST for g(r,z) = 0 - only one full DST inversion

12 Results

13 Contour integrals for q(ψn) #26827 q(ψ N )= R o B o 2π 1/ R 2 B pol dψ C q(ψn) at 5 values of ψn Spline interpolation to calculate ψn and ρn of 3 rational surfaces. Send real-time values to TORBEAM.

14 Integrals for li, βp, Rc, Zc #26827 S1= s 2 V(µ o I p ) 2 l i = s 2 V(µ o I p ) 2 B2 pol ((R R o )r µ +Zz µ ) n µ ds S2= s 2 C V(µ o I p ) 2 C B2 pol Rr µ n µ ds B 2 pol dv β p = 0.5S1+(1 0.5(1 R C /R o ))S2 0.5l i Γ pl

15 Basis function tuning

16 NTM stabilisation M.Reich, A.Bock ρ(ece); 0.55 ρ(fpr); 0.6 ρ(gs); 0.55 Require misalignment < half island width Basis function can be tuned for agreement MSE needed to obtain q profile without tuning Stabilization and prevention of the 2/1 neoclassical tearing mode for improved performance in DIII-D, R.Prater, R.J. LeHaye et. al, NF, 47,371, rtefit with MSE in 6 ms cycle time with 5 coefficients

17 MSE constraints tan(γ m ) = c 1 B r + c 2 B t + c 3 B z + c 4 E r / vbeam c 5 B r + c 6 B t + c 7 B z + c 8 E r / vbeam + E z / vbeam (c 1 c 5 tan(γ m ))(B rp + B rc ) + (c 3 c 7 tan(γ m ))(B zp + B zc ) = (c 2 c 6 tan(γ m ))(B tp + B tc ) 10 extra terms in response matrix A cycle time of 0.8 ms for 6 coefficients with an extra 10 constraints from MSE. Solution with and without MSE constraints in parallel. tan(γ m ) tan(γ m )

18 LabVIEW RT diagnostics Data acquisition systems for new campaign : Magnetics (80 channels) Hz bandwidth at 10 khz Magnetics (220 channels) - broadband replacement at 10 khz Halo current (96 channels) up to 200 khz and 100 khz bandwidth Loop voltage (8 channels) at 50 khz and 25 khz bandwidth MP coils (36 channels) for U and I of 16 coils at 10 khz In-line ECE (8 channels) at 100 khz ICRH (96 channels) at 250 khz or 500 khz Bolometer (128 channels) bridge measurements [FPGA+AD7730] Manometer (4 channels) - ionization gauge for neutral flux [FPGA]

19 DAQ Hardware Dell Precision T quad core Intel Xeon X GHz processors 2 GB memory and LabVIEW RT 2011 PXI-PCIe 8362 MXIexpress bridge (copper) : 160MB/s per slot 2 PCIe x PCIe x16 (Gen2)+ PCI + PCI-X slots + GB Ethernet 2/4 x18 slot PXI 1045 chassis 27 PXI 6143 S Series cards - 16 bit ADC's 216/512 channels simultaneously sampled at 10 khz Dual socket (LGA 2011) with Intel Xeon E upgrade planned

20 SWIP Commissioning GS solver for HL-2A (Dr. F. Xia) Interest in applying Control and Simulation Module for plasma current, position and shape control Simulation Measurements

21 Summary Magnetic data acquisition upgraded to 10 khz for discharge duration Real-time magnetic equilibria available to control system with a cycle time sufficient for soft control applications such as NTM stabilisation For magnetics only using 4 fit coefficients ( ρ(3/2) tuned to give agreement with ECE fluctuation value ) For magnetics + MSE : 6 fit coefficients available for experiments ( essential for robust ρ(m/n) calculation ) GS solver magnetics only with 0.49 ms cycle time on 4 cores GS solver magnetics+mse with 0.80 ms cycle time on 4 cores NI Scientific Computing group contract for DST/tridiagonal/iDST solver LabVIEW RT single thread solution with algorithm improvements L.Giannone et. al, Real-time ISOFLUX calculations as next step

22 NTM experiment overview MA MW T au rhpol AB:27348/AUGD/MAG(0)/Ipi AB:27348/AUGD/FPG(1)/Wmhd AB:27348/AUGD/NIS(1)/PNI AB:27348/AUGD/ECS(1)/PECRH AB:27348/AUGD/BPD(1)/Pradtot AB:27348/AUGD/MAI(0)/BTF AB:26827/AUGD/MAI(0)/BTF AB:26827/AUGD/TBM(1)/Jpol_in;26 AB:27348/AUGD/TBM(1)/Jpol_in;26 AX:27348/AUGD/MRH(1)/enN=2 AX:27348/AUGD/MHA(0)/C AM:27348/AUGD/DCS(1)/XECRH2G Time (s) cview (gdc) v User: magx - Mon Jul 25 16:19: magx/cview/stdset/ntmover.cvs : 27348

23 Diamagnetic loop Find set of coefficients to compensate for pick up from vertical field coils. Make BMC8 calculations (J.Stober) available for MAY diagnostic (An experimentally difficult) additional constraint for magnetic equilibrium reconstruction? 0-1 AA:27336/AUGD/MAI(0)/DIAKM AB:27336/AUGD/MAI(0)/IV1o AC:27336/AUGD/MAI(0)/IV2o AD:27336/AUGD/MAI(0)/IV1u AE:27336/AUGD/MAI(0)/IV2u AF:27336/AUGD/MAI(0)/IV3o AG:27336/AUGD/MAI(0)/IV3u AH:27336/AUGD/MAI(0)/BTF 1, 1.e V D V C = C 1 di V dt + C 2 di V dt e t/τ Time (s)

24 Connecting...

25 Comparison CLISTE - FPR - FPP #26827 Equilibria: 3.1s EQI(1) 3.101s FPR(1) #26827 Equilibria: 4.001s FPR(1) 3.99s FPP(1)