Lichtenberg figures using polarity sensitive powder mixture.

[haversin]

Negative discharge on the right done first and positive discharge on the left done second. Pink color represent positive charge and off white yellow color represent negative charge. Center of the figures show a smaller discharge of opposite polarity due to a oscillation in the system. Both figures formed with about 100 kV across 100 pF capacitor charged using a VDG.

[Weston]

This looks really interesting!

Whats a polarity sensitive powder / how is it made? I am not familiar with the term.

Does each particle contain an electret material or something and then it orients with the electric field polarity?

[haversin]

A polarity sensitive powder mixture (My own name for it) is made with two different powders that upon mixing triboelectrically charge to different polarity's. When this mixture is dusted onto a charged surface the positively charged component powder will be attracted to the negativity charged surface and vice versa.
The mixture I'm using is 5 parts by volume red food coloring dyed cornstarch mixed with 3 parts Lycopodium powder.