Collisional Data for Edge Studies

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September 2009

This section includes neutral particle transport modeling and diagnostics, H-recycling and He-exhaust. All the molecular data are needed for different hydrogen isotopes, including mixed molecules like DT.

  • Elastic collisions, charge transfer, inelastic collisions of H, H2, H+, H2+, H3+ with H2 at low and intermediate energies (0 to 10 keV). Much data have been produced, but much more are needed.
  • H- + H, H2 (e.g. detachment, excitation, dissociation)
  • Electronic excitation and ionization of vibrationally excited H2*(v) and H2+(v) in low-energy collisions with e (including dissociative processes and information on energy distribution of reaction products). The NIFS-DATA-73 and the APID vol. 13 (CRP on "Molecular Processes in Fusion Plasmas") are covering a significant part of these needs, as cross sections for H2+ and the rate coefficients for dissociation of H2*(v).
  • Inelastic electronic collision processes of He, He+, He2+ and excited states of H, He and H2 at low energies.
  • Inelastic collision processes of He, He+ and He2+ with H, H+, H2, H2+ at low energies, including processes with excited H, He and H2.


Despite considerable progress made in CRP work, there continues to be a need for data production and evaluation for collisional data for hydrocarbons and other molecules relevant to fusion devices:

  • Further development of the databases for hydrocarbons, H2O and CO, and Be-, B- oxides and hydrides (including their ions).
  • For hydrocarbons, all processes with electrons and protons should be considered including vibrational excitation.
  • Particle interchange reactions among primary species, C, O, metals and hydrocarbons. Some data are published in APID 13 on "Molecular Processes in Fusion Plasmas" and NIFS and FZ Julich Reports on hydrocarbons
  • There is much interest in CH excitation and a need for state resolved data.


Regarding collision processes of high-Z impurities, the CRP on "Atomic Data for Heavy Element Impurities in Fusion Reactors" is addressing some of these issues, concentrating on W and the noble gases. A CRP on tungsten will be initiated in 2010.

  • Data are needed in priority order for collisions of abundant ions and neutrals of W, Ar, Kr, Xe, Mo and V with e, H+, H, H2. Amongst the W stages, the neutral and singly ionized are of especially high priority.


From previous data priority lists, the following data needs have been addressed. Existing databases appear to be sufficient at this time and no new requests have been made recently:

  • Elastic and momentum transfer ion-neutral and neutral-neutral collisions in the energy range 0.1 eV - 1 keV/amu, involving H, H+, He, He+, He2+, H2 and H2+.
  • Ro-vibrational electronic excitation and attachment for D2, T2, DT.
  • Completion of collisional databases for Be, B and their ions. It includes collision processes of Beq+, Bq+ with electrons.


Data are needed for edge temperature (threshold to ~500eV) charge exchange processes among intrinsic impurities and plasma components:

  • Collisions of Xq+ (X = W, Be, C, He, N, O, Li, B of highest priority, with Cl, V, Ti, Cr, Fe, Ni, Mo of lower priority) with H, H2, He, H+ and H2+ including state selective electron capture.
  • Data are needed for all processes of N, N2, Kr, Ne, Ar and Xe with e, H, H+, H2, H2+, He+, and H- (for the proposed radiative cooling scheme of divertors and radiative mantle).


October 2007

  • Elastic and momentum transfer ion-neutral and neutral-neutral collisions in the energy range 0.1 eV - 1 keV/amu, involving H, H+, He, He+, He2+, H2 and H2+. Some combinations, e.g. He+ + He2+, + on He, H2 still not done. Excited states and higher energies still need to be done.
  • Ro-vibrational electronic excitation and attachment for D2, T2, DT
  • Elastic collisions, charge transfer, inelastic collisions of H, H2, H+, H2+, H3+ with H2 at low and intermediate energies (0 to 10 keV).
  • H- + H, H2 (e.g. detachment, excitation, dissociation).
  • Regarding interaction of the neutral beam with the plasma, collisions involving H* are of importance.
  • Electronic excitation and ionization of vibrationally excited H2*(v) and H2+(v) in low-energy collisions with e (including dissociative processes and information on energy distribution of reaction products). The CRP on "Molecular Processes in Fusion Plasmas" has produced initial work on cross sections for H2+. The rate coefficients for dissociation of H2*(v) are calculated. The NIFS-DATA-73, APID issue in preparation is covering a significant part of these needs. The new 2005 CRP on "Atomic and Molecular Data for Plasma Modelling" initiated) also addresses this topic.
  • Inelastic electronic collision processes of He, He+, He2+ and excited states of H, He and H2 at low energies. This is mostly addressed by the 2 CRPs:
    • CRP on "Molecular Processes in Fusion Plasmas"
    • CRP on "Atomic and Molecular Data for Plasma Modelling"
  • Inelastic collision processes of He, He+ and He2+ with H, H+, H2, H2+ at low energies, including processes with excited H, He and H2:
    • CRP on "Molecular Processes in Fusion Plasmas"
    • CRP on "Atomic and Molecular Data for Plasma Modelling"
  • Completion of collisional databases for Be, B and their ions. This will include collision processes of Beq+, Bq+ with electrons, and quasi-resonant processes of Beq+, Bq+ with H, He and H2.
  • Further development of the databases for hydrocarbons, H2O and CO, and Be-, B- oxides and hydrides (including their ions).
  • For hydrocarbons, all processes with electrons and protons should be considered including vibrational excitation and the effect of this excitation on the dissociation processes, as vibrational excitation might affect dissociation. This is partly covered by concluded and active CRPs.
  • Particle interchange reactions among primary species, C, O, metals and hydrocarbons. Data published for electronic collisions, CRP on "Molecular Processes" adding considerable data for hydrocarbons. NIFS and FZ Julich Reports on hydrocarbons.
  • Collision processes of high-Z impurities in priority order (W, Mo, V, Ar, Kr, Xe) with e, H+, H, H2. CRP on heavy elements initiated in 2005.
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