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Comparison of ITER Baseline Scenario Ramp-Up Simulations with CREATE-NL+JINTRAC: Preliminary Results

This study compares the results of ITER baseline scenario ramp-up simulations using the CREATE-NL and JINTRAC codes. The simulations analyze the determination of the poloidal flux map and the plasma shape control based on a feedforward+feedback control strategy. The results show the evolution of the desired and achieved gap distances, as well as the deviation from the desired gap distances. The comparison also includes the analysis of ECRH-assisted and ohmic ramp-up simulations.

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Comparison of ITER Baseline Scenario Ramp-Up Simulations with CREATE-NL+JINTRAC: Preliminary Results

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  1. ITER baseline scenario ramp-up simulations with CREATE-NL+JINTRACComparison CoppiTang/Bohm-gyroBohm- preliminary results F Koechl

  2. CREATE-NL: Axial-symmetric free boundary code based on numerical solution of Grad-Shafranov equation: Determination of poloidal flux map by FEM discretisation and Newton based iterative method: Plasma shape control is based on a feedforward+feedback control strategy. A PF coil power supply nominal voltage waveform has to be calculated for the scenario.

  3. CREATE-NL (2): Feedback control by calculation of correction voltages to keep plasma shape close to reference evolution described by wall-plasma gap distance time histories.  and boundary evolution as main output for transport code JINTRAC: Feedback controller synthesis based on a linearised model of plasma-circuit response:

  4. Code coupling scheme: Reiteration between CREATE-NL and JETTO-internal equilibrium solver ESCO, until consistency is reached in terms of , f, and q: JETTO CREATE-NL reiterate until ESCO First iteration Further iteration(s)

  5. Simulation conditions: • Typical ITER ramp-up configuration for baseline scenario. • Coupled simulation from t = 15s onwards. • Equilibrium recalculation every 50 ms. • Coarse mesh for equilibrium reconstruction! • Current controller derived from feedforward calculation after offline iteration with JETTO. • 10 MW ECRH from t = 20s onwards. • Prescribed ne, predicted Te/Ti/q. • Comparison CoppiTang model with Bohm/gyroBohm model (without non-local multiplier).

  6. Coppi-Tang Bohm/gyroBohm BETP LI WTH VOL

  7. t = 20s t = 40s

  8. Evolution of desired and achieved gap distances (Coppi-Tang case): Top gap Left equ. gap Right equ. gap Left sweep Right sweep

  9. Deviation from desired gap distances (Coppi-Tang case):

  10. Deviation from desired gap distances (Bohm/gyroBohm case):

  11. t=40s NE TE TI Q JZ

  12. Comparison ECRH-assisted (solid) and ohmic (dash-dotted) ramp-up simulations with evolving but prescribed separatrix: t=40s

  13. Strong increase in beta_pol with CoppiTang model (factor 2.5) compared to Bohm/gyroBohm case due to ECRH and strong dependence of CoppiTang form factor on shape of power deposition profile. • Deviation between achieved and desired plasma shape evolution measured in terms of gap distances increases by factor ~2. • Strong deviation from expected evolution of plasma properties leads to increased amplitude and error of calculated correction coil currents. • CoppiTang simulation might therefore not survive at t>40s.

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