Charge-exchange excitation and recombination of oxygen in theISX−Btokamak

Several spectral lines produced by charge transfer of neutral-beam hydrogen atoms with completely ionized oxygen have been detected in the impurity studies experiment $B$ ($\mathrm{I}\mathrm{S}\mathrm{X}-B$) tokamak, and have been used to compute the absolute concentrations of ${\mathrm{O}}^{8+}$. charge-exchange recombination is found to have a minor effect on the total radiative losses, but enhanced transport during neutral-beam injection appears to raise the oxygen radiation from the interior of the discharges by factors of 3 to 5. This result may reflect an increase of anomalous transport rates that could account for the density "clamping" often observed with injection.