The variation with temperature of positive streamer properties in air

Measurements are reported of the variation of the electric field required for propagation of positive streamers in air as a function of ambient temperature. Propagation velocities have also been measured as function of field and temperature. The results are discussed in terms of changes of air density consequent upon the temperature changes and comparisons are made with other work in which density has been changed by variation of pressure at constant temperature. There is some evidence that specific temperature effects exist. The variation of streamer velocity with air density indicates that a constant reduced total field E/N is maintained in the avalanches, replicating the streamer tip as the density is changed.