Voltoscope

Voltoscopes were beams of energy fired from hoverbouts that the Daleks used to trap Terrorkons after many had attacked a weapons installation the Daleks had built on Skaro. (TV21: The Terrorkon Harvest)

Behind the scenes
A Voltoscope was also listed in The Dalek Book where it was described as a Small arms device, the description explained further that:
 * This is a transistorized torch. Into the size of a normal torch, they have concentrated the power of a thousand suns. This flashed into the eyes of an advancing enemy, creates temporary blindness. Imagine having a huge searchlight being shone straight into your eyes and you have some idea of the intensity of the beam.