1. Examples of using Langevin equation to solve FP equation

2. ASCOT Racetrack for tokamak particles Ab initio particle loading –Fusion alphas (thermonuclear, beam-target, beam-beam) –NBI-generated ions Realistic orbit tracing –Guiding center (4th order RK, w/ 5th order error check, fast) –gyro orbit (Leap Frog, accurate, slow) Fully 3D –3D magnetic field –3D Wall Comprehensive interactions –Coulomb collisions –(Turbulent transport) –Models for relevant MHD: NTM-type magnetic islands Alfven Eigenmodes

3. ASCOT4 Technical details Parallelization –MPI parallel testruns (HELIOS) with 16384 cores –Production runs with 4096 File I/O –Single process does all file I/O –HDF5 format, partly ASCII –Processing of data w/ MATLAB Magnetic field interpolation –PSPLINEs Programming approach –ASCOT completely rewritten in 2012-13 –Modular F90 –Only 2 libraries reguired: HDF5 & MPI

4. FUSION ALPHAS & ITER 1ST WALL

5. Axisymmetry vs ripple vs FI Fusion alphas in 15MA scenario Axisymmetric B fieldWith bare ripple Ripple w/ FI’s

6. Also wall shape matters... Original wall w/ 2 limiters Present wall design w/ poloidally extended ’continuous’ limiters

7. TBM MOCK-UP EXP’S AT DIII-D

8. Ripple map w/ and w/o TBM field bump TBM field bump Max field perturbation along separatrix close to 5% with TBM mock-up Variation of the toroidal field with the TBM coils in the absence of TBM coils BTBT φ TF ripple

9. NBI-generated deuterons in DIII-D discharges w/ TBM mock-up limiters TBM mock-up coils

10. Beam-target DD reaction  T(1 MeV) Guiding-center following clearly not applicable  follow full gyro motion (FO integration)

11. DD  DT  n (14 MeV) Experimental neutron flux in the TBM mock-up experiment Fraction of confined tritium in the plasma as calculated by ASCOT M. Schaffer & al, Nucl. Fusion 51 (2011) 103028

12. IMPURITY INJECTION EXP’S @AUG

13. The case of missing 13 C in AUG Besides fast ions, tritium retention is a hot issue for ITER   Global impurity migration studies in AUG by injecting 13 CH 4  post mortem analysis of samples from selected wall tiles -> 90% missing??  Common assumption: axisymmetric 13 C deposition  ASCOT simulation w/ a 3D wall and magnetic field: notable non- axisymmetry in 13 C deposition (limiters, ICRH antennas, …) [J. Miettunen et al., NF 52 (2012) 032001]