Rovibrationally Resolved Time-Dependent Collisional-Radiative Model of Molecular Hydrogen and Its Application to a Fusion Detached Plasma

Keiji Sawada,Motoshi Goto

doi:10.3390/atoms4040029

Keiji Sawada, Motoshi Goto

Open Access

https://doi.org/10.3390/atoms4040029

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Journal: Atoms	Publication Date: Dec 20, 2016
Citations: 24	License type: CC BY 4.0

Affiliation: Shinshu University, National Institute for Fusion Science

Abstract

A novel rovibrationally resolved collisional-radiative model of molecular hydrogen that includes 4,133 rovibrational levels for electronic states whose united atom principal quantum number is below six is developed. The rovibrational X 1 Σ g + population distribution in a SlimCS fusion demo detached divertor plasma is investigated by solving the model time dependently with an initial 300 K Boltzmann distribution. The effective reaction rate coefficients of molecular assisted recombination and of other processes in which atomic hydrogen is produced are calculated using the obtained time-dependent population distribution.

Highlights

The collisional-radiative model (CR model) [1] provides population distributions of atoms and molecules
We develop a CR model in which the electronic, vibrational and rotational states are considered in order to model molecular processes whose cross-sections strongly depend on the initial vibrational and rotational states, e.g., the dissociative attachment of electrons in Molecular-assisted recombination (MAR)
We applied the H2 CR model to a fusion detached plasma as an example of the application of the present model using the following parameters taken from a SlimCS DEMO detached plasma simulation [12,13]: Te = TH+ = TH = 2 eV, ne = nH+ = 1016 cm−3 and nH = 1015 cm−3

Summary

Introduction

The collisional-radiative model (CR model) [1] provides population distributions of atoms and molecules. Using this model, the effective reaction rate coefficients of various atomic and molecular processes including the contributions of the excited states can be calculated based on the population distribution. A CR model for molecular hydrogen in which only the electronic states are considered was constructed by Sawada and Fujimoto [2]. This model was used to calculate effective reaction rate coefficients of dissociation and ionization of the molecule in plasmas. This CR model was extended by Greenland and Reiter [3] and

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