Observation of the Reaction ${\mathrm{H}}^0$ + ${\mathrm{O}}^{8+}$ → ${\mathrm{H}}^{+}$(${\mathrm{O}}^{7+}$) during Neutral-Beam Injection into ORMAK

Several lines of O viii have been investigated during the injection of hydrogen atoms at energies of 10, 15, and 30 keV into the Oak Ridge tokamak (ORMAK). The Lyman-$\alpha$, -$\beta$, and -$\gamma$ lines and the Balmer-$\beta$ line exhibit slowly increasing signals, but the intensity of the Balmer-$\alpha$ line increases sharply as soon as injection begins. This prompt signal is interpreted to be the direct result of charge transfer from hydrogen to ${\mathrm{O}}^{7+}$ ions in excited states.