examples of using langevin equation to solve fp equation
DESCRIPTION
Examples of using Langevin equation to solve FP equation. 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) - PowerPoint PPT PresentationTRANSCRIPT
Examples of using Langevin equation to solve FP equation
ASCOTRacetrack 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
ASCOT4Technical 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
FUSION ALPHAS & ITER 1ST WALL
Axisymmetry vs ripple vs FIFusion alphas in 15MA scenario
Axisymmetric B field With bare rippleRipple w/ FI’s
Also wall shape matters...
Original wall w/ 2 limiters Present wall design w/ poloidally extended ’continuous’ limiters
TBM MOCK-UP EXP’S AT DIII-D
Ripple map w/ and w/o TBM field bump
TBM field bump
Max field perturbation along separatrix close to 5% with TBM mock-up
)()(
)()(),(
minmax
minmax
BB
BBzR
Variation of the toroidal field• with the TBM coils• in the absence of TBM coils
BT
φ
TF ripple
NBI-generated deuterons in DIII-D discharges w/ TBM mock-up
limiters
TBM mock-up coils
Beam-target DD reaction T(1 MeV)
Guiding-center following clearly not applicable follow full gyro motion (FO integration)
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
IMPURITY INJECTION EXP’S @AUG
The case of missing 13C in AUG
Besides fast ions, tritium retention is a hot issue for ITER Global impurity migration studies in AUG by injecting 13CH4 post mortem analysis of samples from selected wall tiles ->
90% missing?? Common assumption: axisymmetric 13C deposition ASCOT simulation w/ a 3D wall and magnetic field: notable
non-axisymmetry in 13C deposition (limiters, ICRH antennas, …)
[J. Miettunen et al., NF 52 (2012) 032001]