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To evaluate the impact of transport of metastable, vibrationally excited states of the hydrogen molecule in dense and cold plasmas each vibrational state must be simulated as an individual species. Eirene neutral gas simulations of a one‐dimensional flux‐tube using a metastable‐resolved model indicate a 30–50% decrease in the effective dissociation rate compared to simulations using a metastable‐unresolved setup, which consider a single molecular species. Zero‐dimensional Eirene simulations omitting transport effects predict a 25–65% decrease in the effective dissociation rate due to differences between the metastable‐unresolved AMJUEL and the metastable‐resolved H2VIBR rates available in Eirene. The exclusion of molecular hydrogen depletion via electronically excited states and vibrational transitions v→v±N,N>1 from the metastable‐resolved rates reduce the effective dissociation rate. By accounting for the difference caused by the different collisional‐radiative treatment of the metastable‐resolved rates compared to the metastable‐unresolved rates, transport effects are expected to be relevant under detached divertor conditions. It is, however, not possible to individually assess the role of the collisional‐radiative processes and transport on the effective dissociation rate using the currently available atomic and molecular rates for the metastable‐resolved and metastable‐unresolved Eirene setups. [ABSTRACT FROM AUTHOR]

An rovibrationally resolved collisional‐radiative model of molecular hydrogen (K. Sawada and M. Goto, Atoms 4: 29, 2016) is included in the authors' neutral transport code for large helical device (LHD) plasmas. The spatial distributions of the electron temperature and density, including the divertor and divertor leg regions, are given to the code. The molecules released from the graphite divertor target are tracked. The initial rotational and vibrational states of the released molecules are provided by simulation using a molecular dynamics model. The rovibrational population produced in an LHD plasma is evaluated. [ABSTRACT FROM AUTHOR]

The attachment mode of arc on anode is closely related to the non‐equilibrium chemical kinetics process of the anode region of arc. In this paper, the detailed chemical reaction mechanisms in the flow‐affected region for both diffuse and constricted argon arc attachments are investigated by means of one‐dimensional discharge coupled with a single‐fluid, two‐temperature model. The collisional‐radiative model is used to examine the chemical reaction processes occurring in the anode region, including the arc centreline and fringe region. The numerical results are validated by comparison with available experimental data. The obtained radial distributions of electron temperature, electron density, excited states densities, ionization, and recombination processes reveal that different mechanisms dominate the diffuse and constricted arc‐anode attachments. [ABSTRACT FROM AUTHOR]