[Table of Contents]

Plasma and Fusion Research

Volume 6, 2401125 (2011)

Regular Articles

A Collisional-Radiative Model for Hydrogen Atom Including Velocity Changing Collisions
Keisuke FUJII, Taiichi SHIKAMA, Keiji SAWADA1), Motoshi GOTO2), Shigeru MORITA2) and Masahiro HASUO
Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
1)
Department of Applied Physics, Faculty of Engineering, Shinshu University, Nagano 380-8553, Japan
2)
National Institute for Fusion Science, Toki 509-5292, Japan
(Received 7 December 2010 / Accepted 24 June 2011 / Published 26 August 2011)

Abstract

We develop a collisional-radiative model for calculating the velocity distributions of excited hydrogen atoms. In the model, the velocity distributions are approximated using linear combinations of several basis functions which are treated as discrete velocity states, and only charge exchange collisions with proton are considered as velocity changing collisions. The populations in the velocity and excited states are calculated under an assumption of a quasi-stationary state. With the model we derive the velocity distribution of the ground state atoms from that of excited atoms in the n = 3 level observed for an LHD plasma, where n is the principal quantum number. The mean kinetic energy of the ground state atoms is estimated to be 5.6 eV, which is 0.05 eV less than that of the n = 3 atoms.

Keywords

collisional-radiative model, hydrogen atom, velocity distribution, charge exchange collision, velocity changing collision, LHD plasma, spectroscopy

DOI: 10.1585/pfr.6.2401125

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This paper may be cited as follows:

Keisuke FUJII, Taiichi SHIKAMA, Keiji SAWADA, Motoshi GOTO, Shigeru MORITA and Masahiro HASUO, Plasma Fusion Res. 6, 2401125 (2011).