Transfer of ITER SOLPS4.2 simulations to SOLPS5.1 X. Bonnin (CNRS-LIMHP), A. Kukushkin (ITER), D. Coster (IPP-Garching) ● ITER divertor and SOL have been modelled with SOLPS4.2 (A. Kukushkin, H. Pacher, G. Pacher, et al.) ● Large library of results ● Contains extended physics package for neutrals and pumping, including Eirene “face-lift” ● But no drifts, no currents, and little current physics development ● The more recent SOLPS5 package includes the latest physics and is the currently supported version ● Treatment of X-point area much improved by use of indirect addressing ● SOLPS5.1 = SOLPS5.0 + Eirene “face-lift” ● So we are currently attempting to migrate the ITER library of SOLPS runs from 4.2 to 5.1 ● Paying attention to recover old results ● With benefits of new physics to advance in the design ● Documenting the changes from one version to another

Strategy ● Continue a SOLPS4.2 run with SOLPS5.0  Wrote a converter to take SOLPS4 input/output files into SOLPS5 format  Single time-step. Re-evaluate fluxes and examine output  Added new diagnsotics (radiation, bremsstrahlung) to SOLPS5.0  Implemented the detailed particle balance treatment necessary to resolve the ITER pumping fluxes ● Identified several differences/mistakes  Example: Luciani correction on closed field lines: ● SOLPS4: D → D/(1 + 3e15 * T^2/(ne * Z^2)) (1) ● SOLPS5: D → D/(1 + (3.75e16/L) * ) (2)  Implemented a series of switches for „backward compatibility“ of SOLPS5

Some of the identified issues NatureSOLPS4.2SOLPS5.0ImpactStatus Cell volumesparallelepipedsGeneralized quadrangles ~ 1 %OK Area for fluxesOK Missing cos  factor Up to 70% near X-point Fixed (switch introduced) Int. schemes for fluxes UpwindHybridSmallSwitch introduced Int. schemes for flux limits Used average value (no ions) Used maximum value SmallSwitch introduced Luciani modelEq. 1Eq. 2Important for core parallel fluxes Switch introduced Classical transportBraginskiiBalescuNoticeableSwitch introduced VelocitiesCell-facedCell-centeredSmallN/A CurrentsNoneIncomplete zeroing Up to 50 % of el. Energy flux Fixed Ion temperature equation Total energyInternal energyDominatingIn progress

Ion temperature equations SOLPS4: total energy SOLPS5: internal energy

Flux comparisons (I): past the X-Point # fnisip fnisap feisip feisap feesip feesap 4.0_short E E E E E E _with_4.0_short E E E E E E _with_4.0_area_fix E E E E E E _with_4.0_luciani E E E E E E _with_4.0_b2tqce E E E E E E _with_4.0_b2tqca E E E E E E _with_4.0_mode E E E E E E _with_4.0_poteq E E E E E E _with_4.0_ E E E E E E _with_4.0_ E E E E E E _with_4.0_ E E E E E E _with_4.0_ E E E E E E _with_4.0_no_solve E E E E E E _with_4.0_solve_ua E E E E E E _with_4.0_solve_co E E E E E E _with_4.0_solve_ht E E E E E E+07

Flux comparisons (II): at the targets # fnixip fnixap feixip feixap feexip feexap 4.0_short E E E E E E _with_4.0_short E E E E E E _with_4.0_area_fix E E E E E E _with_4.0_luciani E E E E E E _with_4.0_b2tqce E E E E E E _with_4.0_b2tqca E E E E E E _with_4.0_mode E E E E E E _with_4.0_poteq E E E E E E _with_4.0_ E E E E E E _with_4.0_ E E E E E E _with_4.0_ E E E E E E _with_4.0_ E E E E E E _with_4.0_no_solve E E E E E E _with_4.0_solve_ua E E E E E E _with_4.0_solve_co E E E E E E _with_4.0_solve_ht E E E E E E _with_4.0_solve_uaco E E E E E E _with_4.0_solve_uaht E E E E E E _with_4.0_solve_coht E E E E E E+06

Remaining issues ● Ion temperature equation  Most terms in code can now flip between the two formulation according to a switch  Missing the viscous and kinetic energy terms in the solving step for the equation itself ● SOLPS5.0 (Eirene 96 & 99) instead of SOLPS5.1 (Eirene „face-lift“)  Work currently underway to finalize the coupling (V. Kotov) ● Not all differences between the two codes have been properly explained yet ● Must complete the work with series of automated translation/resubmission/analysis scripts

traces.1: Corrected src_ allocation and Zeff averaging bounds traces.2: As above, without interpolation of velocities in converter traces.3: As 1, with 'eirene_extrap'.eq.0, correction of sources entry argument list, new computation and scaling of residuals, fixed impurity radiation traces traces.4: With dtim=1e-29, as 3, with src00 arrays filled, src_r recoded, residuals and SSEEtot and SSEItot corrected traces.5: As 4, coded the volume calculation from SOLPS4.0 (but not used!) traces.6: As 5, with new (misread) bremsstrahlung treatment traces.7: Using new grid with SOLPS4.0 volumes, bremsstrahlung rate read properly, proper zeroing of 3rd instant of sources traces.8: Corrected bremsstrahlung traces, dt=1.e-9s. traces.9: Sum of absolute values of residuals. traces.10: Changed UA from UP to UU/PIT. traces.11: Corrected SX factor in the fluxes traces 12: Correction 'eirene_fixmap' in fort.31 at cuts traces.13: Correction 'eirene_fixuub'.eq.'2' in fort.31, upb=uub*rrb traces.14: Removed ion flux limiter traces.15: Running with same STRAHL data as SOLPS4.0 traces.16: Removed tailep and fix_cx settings from b2ar. New b2frates. traces.17: SOLPS4.0 Luciani formulation introduced: b2trcl_lluciani.eq.2 traces.18: Introduced SOLPS4.0 formulation of electron classical parallel transport traces.19: Added SOLPS4.0 formulation of ion classical parallel transport traces.20: Run with mode=2, no_solve.eq.1, area_fix=3, no hybrid schemes traces.21: Same as 20, but with more Eirene histories for better statistics and pot=3.1*te/qe traces.22: Same as 21, but with lesser (SOLPS4.0) constant accuracy and corrected no_current treatment, SOLPS4.0 upwind scheme for energy (i&e), SOLPS4.0 treatment for electron flux limits traces.23: Same as 22, but fixed fch_[3|5]2 no_current treatment and with SOLPS4.0-like treatment for particle fluxes computation traces.24: Same as 23, after clean-up of uses of vol,hx,hy,gs (only 1 Eirene call) traces.25: Code as 24, with ion flux limits off, and solving