1. Comprehensive ITER Approach to Burn L. P. Ku, S. Jardin, C. Kessel, D. McCune Princeton Plasma Physics Laboratory SWIM Project Meeting Oct. 15-17, 2007 Oak Ridge National Laboratory

2. LPK-1015072 A comprehensive simulation of an ITER discharge has been completed. Plasma states obtained are being used for testing various aspects of IPS. Using IPS/EPA we have carried out an ITER discharge simulation (a hybrid scenario) using NUBEAM and TORIC for the beam and RF calculations, respectively, via the alternate internal coupling method. We use this comprehensive ITER approach to burn to –test coupling to sophisticated source models in TRANSP –compare with previous calculations with analytic models –provide plasma states for IPS to run in re-play mode for  component development and testing,  comparative studies for resolution requirement, and  testing porting to new computer platforms of other components.

3. LPK-1015073 Outline of Presentation Approach to ITER discharge simulation –EPA in IPS –EPA internal coupling to TRANSP (client-server) –TSC & EPA Physics models and results –discharge scenario –source and current drive models –summary of results Improvements, targets and plans

4. LPK-1015074 In normal mode of operation the equilibrium and profile advance (EPA) component communicates with others via the plasma state and the controller. Plasma State Equilibrium & Profile Advance Dist. Function RF/Beam Source Electric Fields & Others MHD Stability Controller

5. LPK-1015075 However, there is an option in EPA which uses models in TRANSP to calculate the source and current drive in conjunction with the equilibrium and profile evolution. Plasma State EPA -- TSC control advance free-bndy equilibrium advance profiles TRANSP evolve sources heating & currents NB, RF, fusion products control equilibrium profiles sources equilibrium profiles Init, step, save, kill ready, error signal file passing receive request

6. LPK-1015076 The engine driving EPA is the Tokamak Simulation Code TSC. TSC performs free-boundary self-consistent transport evolution in any part of a tokamak discharge. TSC models PF coils and 2-D passive structures with circuit equations. Arbitrary power supply models can be used. TSC runs with feedback control systems –radial position, vertical position, Ip, and shape –sensors and reconstructions –stored energy, current profile, etc.

7. LPK-1015077 Using internal coupling to TRANSP initially facilitates the development of other components in ISP. TRANSP has several high fidelity source models –NB - NUBEAM (orbit following Monte Carlo) –ICRF - TORIC/SPRUCE (full wave), CURRAY (ray-tracing) –LH - LSC (ray-tracing 1D Fokker Planck) –EC - TORAY (ray-tracing, relativistic) –  -particles (orbit following Monte Carlo) TRANSP runs in “interpretive” mode for experimental analysis, but this same approach has been modified to run in “predictive” simulations by passing T(  ), n(  ), q(  ), and equilibrium geometry.

8. LPK-1015078 The case study is a “hybrid” scenario Discharge scenario – off-axis beam and ICRF heating: –3 s ≤ t ≤ 250 s –pre-programmed: z eff, n e, I p ; flattop @ t~240 s n e20 =0.924 @ t=240 s Zeff=1.2 (t 150 s) Ip=12 MA @ t=240 s –total internal energy clamped at 450 MJ –particle confinement time=25 s –energy confinement t< 50 s Coppi/Tang profile consistent model t  50 s relaxed GLF23 and neo-classical Flux contours for the free-boundary equilibrium @250 s B=5.3 T, R=6.2 m, a=2.0 m,  =1.8,  =0.45 ,  p =0.74, q(0)=1.17, q(1)=4.30

9. LPK-1015079 Models for heating and current drive –Neutral beams off-axis (beam tangency 5.295 m), 1 st beam on @ 10s, with partial power and @ 50s with full power, 2 nd beam on @ 110 s. Co, 1 MeV D, full power 16.5 MW. NUBEAM, sample size=1000. –ICRF 1 antenna, 20 MW, 52.5 MHz on @ 170 s, 3 He minority (0.001), power level regulated by the total internal stored energy. TORIC, 31 poloidal modes, 128 radial, 64 angular grids –Alpha particles Monte Carlo fast ion slowing down, sample size=1000. –Source integration time – 25 ms.

10. LPK-10150710 Time Evolution of Power Balance Beam 1+2 ICH+Beam  Total Beam 1

11. LPK-10150711 0.0 0.2 0.4 0.6 0.81.0 50000 100000 150000 0.0 0.2 0.4 0.6 0.81.0 50000 100000 150000 0.0 0.2 0.4 0.6 0.81.0 50000 100000 150000 0.0 0.2 0.4 0.6 0.81.0 100000 200000 300000 400000 500000 rho t=150 st=250 s / (A/Weber) P heat (Watts/m 3 )

12. LPK-10150712 Time Evolution of Central Temperatures Decrease due to increased Zeff 1 st beam (16.5 MW) 2 nd beam (16.5 MW) ICH (20 MW) electron Ion 1 st beam (8 MW) 1 st beam (5 MW)

13. LPK-10150713 Time Evolution of Current Drives Pre-programmed plasma current

14. LPK-10150714 TeTe TiTi Temperature, Density and q Profiles at t=250 s

15. LPK-10150715 nene nini

16. LPK-10150716 Some simulation results during the first 50 s of an ITER discharge with beam turned on at t=10 s. Note the loss of power for t<15 s before the plasma is fully developed. Requested power

17. LPK-10150717 Requests of Improvement, Targets and Plans Simulation under full IPS control –Ease of use readily accessible to users (Kessel, Budney, and others) having templates setup for machines (ITER, KSTAR, JET, NSTX, CMOD, DIII) –Options for NBI and  -particle slowing down NUBEAM, Bounce-averaged FP (ACCOME?), ASTRA package –Options for ICRF TORIC, AORSA (full wave), GENRAY (ray-tracing) –Options for LHCD LSC/ACCOME, GENRAY (1D FP), GENRAY/CQL3D (2D FP) –Options for EC TORAY, GENRAY, GENRAY/CQL3D –Routine use of stability codes PEST, BALLON, DCON NOVA-K –Implement redistribution of fast ions from sawtooth from other MHD modes

18. LPK-10150718 Improvements, Targets and Plans (cont.) EPA enhancement –Add prediction of plasma rotation profile  requires sources from all sources  requires options for momentum transport –Improve density prediction  3 hydrogen species and impurity  pellet fueling model –Include fast ion pressure in equilibrium evolution –Implement new GLF23 (TGLF23, available in Dec) and standardized transport interface  needs to be in parallel (10-100 processors) –Implement options for edge pedestal model (including ELMs) –Porting and benchmarking on Jaguar –Implement interface with machine description files Application of IPS/EPA to additional ITER discharge simulations –ELMy H-mode  Q(0) ≤ 1, useful for testing sawtooth handling in IPS –Steady-State  High  n, stability –Study sensitivity to resolution, calling frequency, etc.