Electrical and spectral characteristics of a tube-to-plate helium plasma generated using dielectric barrier discharge in water

A tube-to-plate dielectric barrier discharge He plasma was directly generated in water by 8 kHz sinusoidal excitation voltage. It was found that the average power, rotational temperature of OH, electronic excitation temperature, electron temperature, and electron density increased linearly with the increase of applied voltage and with the value in the range of 3.65-11.13 W, 427-529 K, 4355-4533 K, 1.15-1.96 eV, and 2.56 × 1014-5.76 × 1014 cm−3, respectively. Furthermore, the optical emission spectrum indicated that active He*, O*, N2*, N2+*, and OH* species existed in He plasma.