Discharge behavior observed by Pockels effect - surface charge distribution measurement

An optical measurement technique based on the electro-optical Pockels effect for dynamic observation of surface charge distribution is employed to observe the dynamic behavior of discharges. Different discharge modes are observed with different electrode gap spacings in a needle-plane electrode system. At zero gap spacing, surface discharge is observed. With the increase of the electrode gap spacing (0.60 mm), the discharge observed contains not only surface discharge, but also space discharge. With further increase of electrode gap spacing (3.00 mm), only space discharge is observed, which consists of a corona discharge and a partial breakdown discharge. Therefore, with the increase of electrode gap spacing, the discharge modes observed transform from a surface discharge to a space discharge.