In air-argon dielectric barrier discharge system,the discharge characteristics in slit boundary are investigated by using the discharge device with two water electrodes.The 10μs-exposed photograph shows that the discharges consist of VD and SD.Optial signals show that the discharge time of VD increases with the applied voltage increases.By observing the discharge photographs,it is found that the filaments spacing increases.And it indicates that the accumulated wall charges increase with the increase of volt...