Electrofreezing of supercooled waterdrops

In an attempt to reduce the complications present in previous electrofreezing experiments, supercooled waterdrops about 3 mm in diameter were suspended aerodynamically in a vertical wind tunnel at temperatures of between −8° and −15°C. Drops were stressed by the application of a steady uniform vertical electric field of magnitude up to and including that causing instability. The collision of supercooled drops, charged and uncharged, with and without external fields was also studied, as was the effect of ‘new’ and ‘aged’ corona products from a metal point at high potential. In no case was an increase in freezing probability observed. For our experimental conditions, in which spurious effects are eliminated, electrofreezing does not occur.