AbstractPlasma discharge fluid simulations indicate a negative streamer can be initiated from the narrow tip of a cone‐shaped, realistically sized hydrometeor in a uniform electric field as low as 0.65Ek. A negative streamer, however, cannot be formed from a cone‐shaped hydrometeor with a slightly smaller base radius or a column hydrometeor under otherwise the same conditions. The simulation also shows the negative streamer is accompanied by a positive streamer. The results present implications for understanding lightning initiation and the physical mechanism of the recently discovered thunderstorm‐related phenomenon called fast negative breakdown. Finally, the initiated negative streamer develops with a relatively constant head radius and velocity in contrast with the expanding and accelerating positive streamer. It appears that the differences between the properties of each polarity of streamer are more pronounced in an electric field below Ek.
