The results of investigating dendrite formation in crosslinked polyeth
ylene for a needle-plane arrangement are described. Experiments have b
een carried out using a pulse voltage with varying front and pulse dur
ations. Positive and negative pulses and a series of different pulses
have been used over a temperature range of 20-90 degrees C. Space char
ge accumulation before dendrite nucleation has been measured by means
of pulses of acoustic pressure and accelerated protons.