Plasma and Fusion Research

Volume 20, 1201031 (2025)

Rapid Communications

Estimation of Ion Density of Helium Plasma using Collisional-Radiative Models in Linear Plasma Device NUMBER
Koki SATO1), Atsushi OKAMOTO1), Takaaki FUJITA1), Yuichi KAWACHI1), Mimami SUGIMOTO1), Muneo KOIKE1), Yuto YAMADA1), Kota TAKEDA1), Kazuhiro TORII1), Hiroyuki TAKAHASHI2)
1)
Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
2)
Tohoku University, Aobayama, Sendai 980-8579, Japan
(Received 13 February 2025 / Accepted 14 April 2025 / Published 17 June 2025)

Abstract

In the linear plasma experimental device NUMBER, the densities of ions and atoms in helium plasma were estimated using passive spectroscopic measurements. The collisional-radiative models were employed to derive the densities of atoms and ions from the measured line intensities of each species. The estimated densities of helium species showed that (1) the atom density is one order of magnitude smaller than that estimated from gas pressure before discharge, (2) the density of singly charged ions is one order of magnitude smaller than that of atoms, (3) the doubly charged ions have a density 4 orders of magnitude smaller than the singly charged ions.

Keywords

spectroscopy, collisional-radiative model, ion fractional abundance, ionization equilibrium

DOI: 10.1585/pfr.20.1201031

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