This next image -from a variation of the previous experiment- shows
electric-wind-caused mirgation of material from margins. Here i brought the
arc-discharge probe above the surface while the lowere arc was still active.
You will see in the video (dahlenaz07 on youtube) that re-deposition of material
to nearby areas occurrs rather fast but that is less important than migration of margins
by invisible dark-mode electrical exchange.
The white surface was not a conductor and this experiment was done at high humidity..