We have calculated time-dependent ion abundances including the C(III)
metastable state 2s2p(3)P (time-dependent metastable model) in order t
o explain the discrepancies between measurements and simulations for t
he visible line intensities of C(III) from JT-60U. It is found that th
e metastable state is produced efficiently by inner-subshell ionizatio
n and remains for a long time comparable with the ground state. Conseq
uently the line intensities of the singlet state decrease whereas thos
e of the triplet states increase compared with the results given by a
quasi-steady-state model. (C) 1997 Elsevier Science S.A.