Plasma-Wall Interaction

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September 2009

Erosion

  • Assessment of data needed for Be, BeO, carbon-based materials and medium- and high-Z materials (W, Ti, V, Mo, Nb). Data for physical sputtering yields are known. Energy dependence at normal incidence is satisfactory. Data for angle dependence is not as complete as for normal incidence. Data on sputtered energy (to allow the determination of the mean energy of sputtered atoms) also exist but have not been fitted, and not yet included in database. This can be done through consultancy.
  • Mixed materials will arise from Be, C and W. Without means of knowing the impurity flux, it is difficult to address this issue, see results from previous CRP on mixed materials. Characterization of the mixed materials is of interest.
  • Characterization of erosion products such as dust, films, flakes etc.
  • Need exists for chemical sputtering for carbon based materials. This is being addressed by the ongoing CRP on "Data for Surface Composition Dynamics Relevant to Erosion Processes".
  • Investigation of erosion and target properties data for materials involved in ELMs and disruptions is important.

Hydrogen isotope reflection, retention and release in fusion materials and codeposited layers

  • H/D/T permeability, diffusivity, solubility, desorption rate and surface reactions. Materials of interest are W, Be, BeO, Mo, carbon based materials, deposited and codeposited layers of these materials. Data on traps in materials. The CRP on "Tritium Inventory in Fusion Reactors" addressed much of this for Be, C and W.
  • Angular and energy distribution of H, D, H-, D- scattering on surface (particularly on C) at glancing angles and energy from 50 keV to 1 MeV
  • Charge state as well as electronic and ro-vibrational (molecular) states for reflected and sputtered particles may be important. Many data are now available for reflection of hydrogen isotopes as well as others such as noble gases, in the energy range of ~10 eV - ~100 keV.

Molecular balance on surfaces

There is a strong need of data in this area, emphasizing inclusion of molecular vibration:

  • Molecule and molecular ion formation and destruction with identification of product charge and quantum state.
  • Data for hydrocarbons and H- formation on surfaces, particle sticking, pumping, gettering, and recycling.


October 2007

Erosion

  • Assessment of data needed for Be, carbon-based materials and medium- and high-Z materials (Ti, V, Mo, Nb, W, BeO). Data on sputtering yields of these are partly available (i.e. for normal incidence).
  • Sputtered energy (to allow the determination of the mean energy of sputtered atoms).

Hydrogen isotope reflection, retention and release in fusion materials and codeposited layers

  • H/D/T permeability, diffusivity, solubility, desorption rate and surface reactions. Materials: W, Be, BeO, Mo, new CFC's, deposited and codeposited layers of these materials. Data on traps in materials. The CRP on "Tritium Inventory in Fusion Reactors" addresses partly this topic.

Molecular balance on surfaces

  • Molecule (molecular ion) formation and destruction with identification of product charge and quantum state. Data for H- formation on surfaces, particle sticking, pumping, gettering, and recycling. (Emphasizing inclusion of molecular vibration in the initial state.)
  • Mean range of impinging particles (and deposition profiles) would give information on the disturbed target region.
  • Gas bubble formation in wall material from alpha particles formed by neutron reactions and protons from neutron reactions and implantation.


November 2005

Disruption erosion

  • Assessment of data needed for Be, carbon-based materials and medium- and high-Z materials (Ti, V, Mo, Nb, W, BeO). Data on sputtering yields of Ti, V, Mo and Yb? are partly available
  • Sputtered energy (to allow the determination of the mean energy of sputtered atoms).

Tritium retention and release in fusion materials and codeposited layers

  • D/T permeability, diffusivity, solubility, desorption rate and surface reactions. Materials: tungsten, beryllium, BeO, Mo, new CFC's, deposited and codeposited layers of these materials. Data on traps in materials. IAEA CRP initiated in 2002 (Tritium Inventory in Fusion Reactors). Work underway in CRP on variety of materials

Molecular balance on surfaces

  • Molecule (molecular ion) formation and destruction with identification of product charge and quantum state. Data for H- formation on surfaces, particle sticking, pumping, gettering, and recycling.
  • Mean range of impinging particles (and deposition profiles) would give information on the disturbed target region.
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