Hydrogen atom recombination on tungsten at high temperature: Experiment and Molecular Dynamics Simulation

• Published in: Surface science 2014-10, Vol.628, p.66-75
• Main Authors: Rutigliano, M., Santoro, D., Balat-Pichelin, M.
• Format: Article
• Language: English
• Subjects: Atom recombination; Chemical Sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Engineering Sciences; Exact sciences and technology; Exothermic reactions; Hydrogen atoms; Hydrogen plasma; Magnetically confined fusion plasma; Materials; Molecular dynamics; Molecular Dynamics Simulation; Physics; Plasmas; Reactive fluid environment; Simulation; Surface reactions; Surface temperature; Tungsten; Walls
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2014.05.007

Atom recombination at wall is a phenomenon involved in many plasma experiments and also in present tokamaks and future fusion plasma reactors like ITER. This exothermic surface reaction is catalyzed by the material and depends on its composition and temperature. In the MESOX experimental set-up, several methods were developed for the measurement of the recombination parameters. In this paper, a method developed for the experimental evaluation of the recombination coefficient of atomic hydrogen γH on tungsten at high temperature is presented using two series of atomic lines (Hα and He or Hβ and H2) and the results obtained for surface temperature up to 1350K are given. A Molecular Dynamics Simulation has been done for the recombination of hydrogen atoms on tungsten in conditions close to the experimental ones using a semi-classical collisional method. Modeling results are compared to the experimental data for two surface temperature values and a fairly good agreement was obtained. •The adsorption/recombination of H atoms on tungsten up to 1350K is measured.•A joint experimental and Molecular Dynamics Simulation study is presented.•The recombination coefficient γH was measured and determined via simulations.•A good agreement between the γH measured and calculated was achieved.