[Phys-L] plasma sphere

[Anthony Lapinski <alapinski@pds.org>]

I understand the basics of how these things work, but I am wondering about
the colored streamers inside the glass. Specifically, why do they change
color near the glass? See photo here:

https://en.wikipedia.org/wiki/Plasma_globe#/media/File:Plasma_globe_60th.jpg

Is it because the glass is a conductor (compared to the gases inside the
globe), and the charge accelerates toward it, which energizes the gas
atoms, and make them emit a different color? I have a large one of these
(diameter = 38 cm). The streamers go from pink to reddish-pink near the
glass.