Sprite halo structures and streamer onset

Imaging of sprites at 16,000 frames per second indicates that streamers may be spawned from spatial structure in the preceding sprite halo. The halo structures descend rapidly with the sprite halo, but slow down and stop to form the stationary glow seen in the vicinity of the streamer onset. The streamers emerge suddenly from the halo structure propagating downwards at ~10⁷ m/s. The velocities during the rapid descend of the halo are similar to those of the streamers. The luminous halo structures last longer than the main halo, which fades prior to streamer formation.