Diagnosis of hydrogen anions (H−,H3−) from the near-electrode region of dielectric-barrier-discharge plasmas

This is the authors' abstract. We don't add key points for this paper.

Hydrogen anions (H−,H3−) from the near-ground-electrode region in dielectric barrier discharge hydrogen plasmas were characterized using a molecular-beam mass spectrometer under the pressure of 1.5–60Torr. The measured H− current is more than one to a few orders of magnitude greater than that of H3− at pressure of 1.5–7.6Torr with a peak-to-peak voltage of 40kV and a 35kHz ac power source. At the gas pressure range of 7.6–60Torr, only the H− ionic signal is observed. The hydrogen-ion currents rise with the increasing of discharge voltage and ac frequency, but exhibit a maximum over the H2 pressure range studied. The dominant formation mechanism for the H− and H3− anions in the alternative and temporary cathode sheath near the discharge electrode has been discussed. The dependence of the mean energy of H− and H3− anions on H2 pressure has been also obtained.