Utilization of D2 molecular band emission for electron density measurement

• DOI: 10.1016/j.nme.2024.101796
• Publication Date: 2024-11-07T00:11:50Z
• Authors: D. Nishijima; M.J. Baldwin; F. Chang; D. Hwangbo; G.R. Tynan
• Keywords: Molecular band emission; Collisional-radiative model; Machine learning; TK9001-9401; 0103 physical sciences; Optical emission spectroscopy; Nuclear engineering. Atomic power; Deuterium; 01 natural sciences

D2 molecular band emission observed at a wavelength range of λ∼557−643nm is utilized to measure electron density, ne, in D plasmas of the PISCES-A and PISCES-RF linear plasma devices. The D2 band is divided at λ=593nm to make an intensity ratio, D2L (∼557–593nm)/D2R (∼593–643nm), where D2L consists predominantly of the g3Σg+3dσ, h3Σg+3sσ, i3Πg3dπ, j3Δg3dδ → c3Πu2pπ transitions, while D2R mainly includes the d3Πu3pπ → a3Σg+2sσ Fulcher band emission. It is experimentally found that D2L/D2R depends strongly on ne with little Te dependence in ranges of ne∼(0.031−6.1)×1018 m−3 and Te∼2.3−13.9eV. This observed trend is consistent with collisional-radiative model calculations using Yacora on the Web.