A Study of Corona Discharges at Water Drops Over the Freezing Temperature Range

Foul weather corona have been observed to behave differently at temperatures above and below the freezing point1.2. Generally speaking, the discharge activities are much more intensive at temperatures above than below the freezing point. Such behaviour of the discharge is so far associated with the differences in the physical properties of water in its liquid and solid phases. No detailed study has, however, been made to correlate the discharges characteristics with the macroscopic changes in the water drop over the freezing temperatures range. In the present study, the development of corona discharge at a watet drop in a cylindrical field was investigated during its transition from the liquid to solid phase. This was done by correlating the discharge current with variations of the water drop temperature. The results obtained show that the noise generation and energy losses are related to both the corona discharges in the surrounding air and to the continuously changing conditions at the water drop during its transition into ice (and vice versa).