This website provides detailed plans to building a plasma globe out of common available parts.
Building such a device is not nearly as hard or expensive as building a tesla coil for example. Although commercial globes often use noble gasses at low pressure, it is not the case with this homemade device. It just uses air at relatively low pressure.This will make the voltage requirement for the central electrode a lot higher.
Also the central electrode in commercial devices is encapsulated in glass. Making this is beyond the reach of most hobby enthusiasts(including yours truly). So this device will just use a simple solid metal ball as the central electrode.
On a final note: this device is not a toy.The voltage on the central electrode is a lot higher than that of commercial globes. Touching the glass while the globe is operating is therefore at your own risk.
“ Not as spectacular as the real thing. But seeing this baby in action is impressive, to say the least.”