Computational Atomic and Molecular Physics for Transport Modeling of Fusion Plasmas

1. Computational Atomic and Molecular Physics for Transport Modeling of Fusion Plasmas Principal Investigators M.S. Pindzola, F.J. Robicheaux, D.C. Griffin, D.R. Schultz, J.T. Hogan Post-doctoral fellows S.D. Loch, J. Ludlow, C.P. Balance, T. Minami Graduate students M.C. Witthoeft, J. Hernandez, T. Topcu, A.D. Whiteford Collaborators N.R. Badnell, M.G. O’Mullane, H.P. Summers, K.A. Berrington, J.P. Colgan, C.J. Fontes, T.E. Evans, D.P. Stotler, P.G. Burke

2. ITER Relevant Plasma Modeling Efforts • Final choices for plasma-facing materials. • Relevance of innovations in operational regimes. • Chief experimental spectroscopic tools need reliable atomic data • Be, C, and W components for the first wall. • Study of Edge Localized Mode (ELM) transient in standard ITER operation

3. ITER Relevant Plasma Modeling Efforts • Two-dimensional, time dependent, multi-species transport code such as SOLPS (B2-Eirene) uses the ADAS database. • Used for analysis at JET, ASDEX-Upgrade, DIII-D, JT-60, Tore-Supra, and Alcator C-Mod.

4. Collisional-Radiative Modeling using ADAS • Originally developed at JET • Now used throughout the controlled fusion and astrophysics communities • Solution to collisional-radiative equations for all atomic levels in all ionization stages of relevant elements. Thus requires • Atomic structure for energies • Radiative rates • Collisional electron excitation rates • Collisional electron ionization and recombination rates • Collisional charge transfer recombination with hydrogen

5. Collisional-Radiative Modeling using ADAS • The problem is simplified through the assumption of quasi-static equilibrium for the excited states. • The following data is produced, for ease of use in plasma transport codes • Generalised collisional-radiative (GCR) coefficients • Radiated power loss (RPL) coefficients • Individual spectrum line emission coefficients • We have completed the following sequences • He, Li and Be

6. AM collision calculations : Time independent R-Matrix • Developed in the UK : P.G. Burke and co-workers • Each atom modeled as : N-electron Hamiltonian • Collision system modeled as : N+1 electron Hamiltonian • Hamiltonian represented by bound and continuum basis states • All eigenvalues and eigenvectors of 50,000 x 50,000 matrix required. This can only be solved on parallel machines. • Thousands of energies required to map out Feshbach resonances

7. AM collision calculations : Time independent R-Matrix • R-Matrix with pseudo states calculations completed for • He, He+ • Li, Li+, Li2+ • Be, Be+, Be2+, Be3+ • B+, B4+ • C2+, C3+, C5+ • O5+ • Standard R-Matrix completed • Ne+, Ne4+, Ne5+ • Fe20+, Fe21+, Fe23+, Fe24+, and Fe25+ Energy vs excitation cross section for neutral Be

8. AM Collisions : Time Dependent Close-Coupling • Developed in the US by C. Bottcher and co-workers • Treats the three body Coulomb breakup exactly • Close-coupled set of 2D lattice equations • TDCC calculations completed for • H, He, He+ • Li, Li+, Li2+ • Be, Be+, Be2+, Be3+ • B2+, C3+, Mg+, Al2+, Si3+ • Have now started to treat • the four body Coulomb breakup • the three-body two Coulomb center breakup Ionization cross section for C2+. Shows the first agreement between theory and experiment for a system with significant metastable fraction.

9. AM Collisions : Time-Dependent Semi-Classical • Developed in the study of heavy-ion nuclear fusion • Electron in the field of two moving Coulomb fields • 3D lattice method solved by low-order finite differences or high-order Fourier-collocation representation. • Applications • p+H, p+Li, α+H, Be4++H, p+H2+ • Hybrid TDSC/AOCC method • 4D lattice close-coupling for p+He

10. AM Collisions : Distorted wave and Classical Trajectory • Uses perturbation theory. • Accurate for radiative and autoionization rates. • Accurate for electron collisions with highly charged ions. • Various levels of calculation • Intermediate coupled distorted-wave (ICDW) • LS coupled distorted wave (LSDW) • Configuration-average distorted-wave (CADW) • Classical Trajectory Monte Carlo (CTMC) Resonance plot for Cl13+ showing the first observation of trielectronic recombination

11. AM Collisions :Distorted wave and Classical Trajectory • Dielectronic recombination project using ICDW for laboratory and astrophysical elements • Li, Be, B, C and O iso-electronic sequences completed • Support for ion storage ring experiments • Cl13+ • Heavy element ionization/recombination using CADW • Ar, Kr, Xe, Mo, Hf, Ta, W, Au • Charge transfer using CTMC • High Z ions with H, D, and He. Bi7+ 5s25p65d8 ionization cross section

12. General Science Spin-offs • TDCC for • (γ,2e) on He, Be, Li+, quantum dots, H2 • (2γ,2e) on He • (γ,3e) on Li • e+ + H • TDSC for • p- + H • BEC in fields • CTMC for • e + atoms in ultracold plasmas • γ + atoms in high Rydberg states

13. Collaborations with existing fusion laboratories - I DIII-D, California Li generalised collisional-radiative coefficients used in impurity transport studies EFDA-JET, UK He R-Matrix excitation data used in helium beam studies, and in non-Maxwellian modeling.

14. Collaborations with existing fusion laboratories - II ASDEX-upgrade, Germany Tungsten ionization data to be used in heavy species studies RFX- Italy Krypton ionization ionization data is being used in plasma transport studies

15. Conclusions • Recent advances in non-perturbative methods allows high quality atomic data to be generated for electron-ion and ion-atom collisions for low Z systems, such as Li, Be and C. • High quality atomic data is being processed into a form useful for plasma transport modeling of wall erosion and ELM experimental studies. • High quality atomic data for high Z systems, such as W, remains a computational grand challenge.