K. Sato

T. Kobuchi

National Institute for Fusion Science (NIFS-Repository)

Fig.1 relative intensity on alII2pSp SD1,2,S-2pSd 3F2,s,4328Exp.326 327wavelength [nm]o...... L.L........ __---I3251.5 r----..,..---__---,.....=1!!rI.l=QJ 0.5=1.5 . .C'l (V) ...... gjXAji,0 1\ 1\(V) ..J.NJ!, J!,J!,rI.l 1 .=.QJ=QJ,...0.5 .-QJpopulations in multiplet levels are statisticallypopulated. The population ratios of 2pSdsF2,s,4 of 0 2+ have to agree with the ratios ofstatistical weights. The observed distinctivefeature on 2pSp sD-2pSd sF suggests that anextra atomic process affects the population of2pSd sF2.In order to investigate whether the similarphenomenon takes place In other lightelements, spectra of the same transition innitrogen have been observed. Since j-j'=1-2and j-j'=2-S of NIl 2pSp sD-2pSd 3F are veryclose, the second order wavelength have beenobserved in order to separate these lines. Theintensity distribution agrees with the expectedratios within the error of several percent. Theobserved anomalous intensity distribution inmultiplet lines is limited in alII 2pSp sD-2pSdsF transition.Kobuchi, T., Sato, K.§ 10. Measurement of Multiplet TransitionSpectra for Light ElementsThe line intensity ratio between multipletlines is interested. So far, we have seen thatthis intensity distribution depends on ne and Te.On OV; the dependence has been examinedtheoretically and experimentally. I(1-2)II(1-1)of OV 2sSs 3S1 - 2sSp SPO,1,2 changes within theratios 2-S for ne =1010-1014 cmos. In particular,since a transition between fine structureincreases with ne, it has been recognized thatthe population of fine structure depends onown statistical weight in high electron densityconditions. Only few attempts have so farbeen made for other elements and ions. Inorder to use the relative line intensity betweenmultiplet transitions for plasma diagnostics, acharacteristic of intensity ratio needs to beinvestigated.The triplet lines 2pSp SD1,2,S· 2pSd sF2,s,4 ofC-like oxygen are frequently observed inplasma diagnostics since they are strong andin the UV-Visible range. However, it isobserved that these intensities have a singulardistribution. In order to investigate thedistinctive feature of this transition, we madean experiment using Test Plasma by Directcurrent discharge II (TPD-II).Shown In Fig. 1 is the intensitydistribution for 2pSp SD1,2,S . 2pSd sF2,s,4predicted by the statistical weight times'transition probability (gj XAji) and the observedresult (helium discharge mixed with 02,JP=100A, R=1.45kG). The line intensities arenormalized by the strongest intensity line,j-j'=S-4. Agreement of intensity distributionbetween the experiment and the expectationhas been confirmed in terms of j-j'=2-Stransition. However, the observed j-j'=1-2transition line is different from the expectedrelative intensity and very weak.The intensity distribution of othertransitions on alII has been observed with thesame discharge condition. They agree withthe expected distribution within the error ofseveral percent. This suggests that the296

Measurement of Multiplet Transition Spectra for Light Elements

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