Observations of gains in the extreme ultraviolet

Observations of gain on the hydrogen-like carbon ion Balmer- alpha transition, C VI H alpha , at 182 AA are examined for consistency and possible sources of error. It is concluded on purely experimental grounds that the only result consistent with the full set of data is that amplification is observed, and that this should be ascribed to gain by stimulated emission. The data are compared with the values obtained by computational modelling and shown to be in satisfactory agreement provided the incomplete burn through is taken into account in accord with the numerical predictions. It is found that the model severely underestimates the gain observed: reasons for this are given.