Computational Atomic and Computational Atomic and Molecular Physics for Transport Molecular Physics for Transport

Modeling of Fusion PlasmasModeling of Fusion Plasmas

Post-doctoral fellows

S.D. Loch, J. Ludlow,

C.P. Balance, T. Minami

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

Principal Investigators

M.S. Pindzola, F.J. Robicheaux, D.C. Griffin,

D.R. Schultz, J.T. Hogan

Graduate students

M.C. Witthoeft, J. Hernandez, T. Topcu, A.D. Whiteford

ITER Relevant Plasma ITER Relevant Plasma Modeling EffortsModeling 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

ITER Relevant Plasma ITER Relevant Plasma Modeling EffortsModeling 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.

Collisional-Radiative Modeling Collisional-Radiative Modeling using ADASusing 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

Collisional-Radiative Modeling Collisional-Radiative Modeling using ADASusing 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

AM collision calculations : AM collision calculations : Time independent R-MatrixTime 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

AM collision calculations :AM collision calculations : Time independent R-Matrix 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

AM Collisions :AM Collisions : Time Dependent Close-Coupling 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.

AM Collisions :AM Collisions : Time-Dependent Semi-Classical 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

AM Collisions : AM Collisions : Distorted wave and Classical TrajectoryDistorted 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

AM Collisions :AM Collisions :Distorted wave and Classical TrajectoryDistorted 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

General Science Spin-offsGeneral 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

Collaborations with existing Collaborations with existing fusion laboratories - Ifusion laboratories - I

DIII-D, California

EFDA-JET, UK

Li generalised collisional-radiative coefficients used in impurity transport studies

He R-Matrix excitation data used in helium beam studies, and in non-Maxwellian modeling.

Collaborations with existing Collaborations with existing fusion laboratories - IIfusion laboratories - II

RFX- Italy

ASDEX-upgrade, Germany

Tungsten ionization data to be used in heavy species studies

Krypton ionization ionization data is being used in plasma transport studies

ConclusionsConclusions 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.