A study of the low-density regions developed in liquefied polyethylene under high electric fields

Low-density regions developed in liquefied polyethylene with a point-plane electrode configuration under high electric fields have been investigated using a Schlieren technique in the temperature range from 120°C to 200°C. The region having a refractive index or a density lower than the surrounding medium is always formed near the point electrode irrespective of its polarity. For polyethylene in the liquid state this disturbance region tends to spread and gradually to disappear on its way of moving from the point to the plane electrode at a temperature-dependent velocity, while in its solid state this region does not move.