Emission from C-, N- and O-Impurity Ions in Linear Pinch He Plasma in Vaccum Ultraviolet λ500 to 1,500A Region

Abstract

The He plasma containing C-and O-impurity ions or N-impurity ions, whose electron density and temperature ranged from 5 × 10¹⁷ to 3 × 10¹⁸cm⁻³ and from 4 to 5 eV, respectively, was produced from He-CO₂ (0.1 mole%) or He-N₂ (0.1 mole%) mixed gas, respectively, in a linear pinch tube, and the observed emission lines in λ500 to 1, 500A region were assigned and classified ; the lines due to the outer 2ₛ-shell electron excitation and those due to the valence 2p-electron excitation for OII-ions, NII-and OIII-ions and CII-, NIII-and OIV-ions, which are specified by the ground state configurations 2ₛ²2pᵐ with m＝3, 2 and 1, respectively, and the lines from the singly and doubly excited levels for CIII-, NIV-and OV-ions, which have the ground state configuration 2S². The relative intensity, the pressure dependence of intensity and the temporal behavior were observed on the spectral lines of both the outer 2ₛ and the valence 2p excitations. A possibility is suggested that the charge exchanges between He⁺ and impurity atoms or ions take place due to the rapid contraction of the plasma. For CIII- NIV-and OV-ions, it is seen that the lines from the doubly excited level 2p²(³P) to the metastable levels 2ₛ2p(³P⁰) show a remarkable afterglow after the pinch of the plasma.