**Computational Atomic and Molecular Physics for**

**Transport Modeling of Fusion Plasmas**

M S Pindzola^1^, F J Robicheaux^1^, S D Loch^1^, D C Griffin^2^, C P
Balance^2^,

D R Schultz^3^, T Minami^3^, J T Hogan^3^, N R Badnell^4^, A D
Whiteford^4^,

M G O\'Mullane^4^, H P Summers^4^, K Berrington^5^, J Colgan^6^, C J
Fontes^6^,

T E Evans^7^ and D Stotler^8^

^1^*Auburn University,* ^2^*Rollins College,* ^3^*ORNL,* ^4^ *University
of Strathclyde,* ^5^*Sheffield Hallam University,* ^6^*LANL,* ^7^*DIII-D
National Fusion Facility,* ^8^*PPPL*

*Summary*

***A DoE Scientific Discovery through Advanced Computing (SciDAC)
program has brought together a collaboration to implement
state-of-the-art atomic and molecular collision codes on the next
generation of terascale computing facilities. Studies are proceeding on
a wide range of atomic collision processes present in controlled fusion
plasmas. Integration of the basic atomic data into transport modeling
efforts for ITER relevant experiments is facilitated by the construction
of derived atomic data using the ADAS collisional-radiative package.
Computational research advances have already been applied to other
general science areas, including laser interactions with atoms and
molecules, x-ray spectra from astrophysical objects, and the dynamics of
cold atom gases.***

**1. ITER Relevant Modeling Efforts**

Experimental efforts are underway worldwide to provide scientific input
needed for critical design decisions and for estimating the future
performance of ITER. In particular, the final choice of material for the
active plasma-facing materials in ITER presents an urgent need for
reliable atomic data which are lacking, at present, in a number of key
areas. These data provide the chief experimental tool for diagnosing the
plasma-wall interaction in present machines.

Previous large-scale atomic collision calculations, through their
interface with the ADAS collisional-radiative codes, are now widely used
in present fusion-related modeling and diagnostic applications.
ADAS-derived atomic data are used in the SANCO and UTC core impurity
transport codes at JET. These data also represent the main source of
atomic data for the SOLPS (also known as b2-Eirene) suite of divertor
transport codes, developed by IPP-Garching and used for analysis of JET,
Asdex-Upgrade, DIII-D, Tore Supra and Alcator C-Mod edge and divertor
experiments.

**2. Derived Atomic Data**

A transport code\'s ability to determine the stage of ionization of an
element at a particular location in a fusion plasma requires knowledge
of generalized collisional radiative (GCR) coefficients, while the
ability to determine the light emitted by an element across all
ionization stages requires knowledge of total radiated power loss (RPL)
coefficients, as supplied by ADAS. In the last year,
collisional-radiative calculations have been completed for Li plasmas
comparing the ADAS and Los Alamos suite of codes\[1\]. Work is in
progress on further ADAS collisional-radiative calculations, using
recent He, Li, and Be electron-ion scattering data, to generate
temperature and density dependent GCR and RPL coefficients for ground
and metastable states of every ionization stage. Dielectronic
recombination data for dynamic finite density plasmas has been generated
for an extensive set of laboratory and astrophysically abundant elements
in the Li, Be, B, C, and O isoelectronic sequences \[2\]. Work is in
progress on further first and second row periodic table isoelectronic
sequences.

##### 3. Atomic Collision Calculations

Our ability to generate accurate atomic data for electron-atom
excitation, ionization, and recombination, as well as ion-atom
excitation, charge-transfer, and ionization is based on the development
of non-perturbative scattering theory over the last decade. All of the
associated computer codes have been adapted for use on massively
parallel architectures, and in the case of high Z atoms remain limited
only by the size of current machines. Over the years we have also
developed a suite of computer codes based on first-order perturbation
scattering theory. For application to moderate to highly charged atomic
ions, perturbative distorted-wave cross sections can be quite accurate.
We are now adapting those codes for use on massively parallel
architectures, especially in the case of high Z atoms. In the last year,
2D lattice time-dependent close-coupling calculations have been
completed for the electron-impact excitation and ionization of
He^+^\[3\], the electron-impact excitation of Li to high principal
quantum numbers\[4\], and for the electron-impact ionization of all
ionization stages of Be\[5\]. Work is in progress for elastic and
inelastic e + H collisions and for the electron-impact ionization of
C^2+^ in both the ground and metastable excited states. Large-scale
R-matrix with pseudo-states (RMPS) calculations have been completed for
electron-impact excitation of He \[6\], Li^+^\[7\], B^+^ \[8\],
C^2+^\[9\], and various light hydrogenic ions \[10\], as well as
excitation and ionization of all ionization stages of Be\[5,11\]. We are
now in the process of performing calculations of the electron-impact
excitation of B, C^+^, and Ne, as well as ionization of H-like and
He-like atomic ions of fusion interest. Configuration-average
distorted-wave calculations have been completed for the electron-impact
ionization of several ionization stages of O\[12\]. Calculations of the
electron-impact ionization of all ionization stages of W are now being
performed. Intermediate-coupling distorted-wave calculations have been
completed for the dielectronic and trielectronic recombination of
Cl^13+^\[13\]. Time-dependent semi-classical lattice calculations have
been completed for laser modified charge transfer processes in p + Li
collisions \[14\], and calculations of charge transfer processes in α +
H, Be^4+^ + H, and proton collisions with excited H and $H_{2}^{+}$ are
now being performed.

##### 

##### 4. General Science Applications

Non-perturbative scattering theory and the associated computer codes can
be easily adapted for the advancement of science in other areas. At the
same time, other applications provide valuable checks on the accuracy of
the general methods. 2D time-dependent close-coupling calculations have
been completed for double photoionization of He in excited states
\[15\]. 3D time-dependent close-coupling calculations have been
completed for double photoionization with excitation and triple
photoionization of Li\[16\]. 2D time-dependent close-coupling
calculations have been completed for the single, double, and triple
photon ionization of $H_{2}^{+}$\[17\]. Time-dependent lattice
calculations have been completed to determine collective modes of ground
and dark soliton states of Bose-Einstein condensates in anisotropic
traps\[18\].

The references can be found on our web page.
http://www.atomic.physics.auburn.edu