Plasma Ball: How Does It Work?

[Suicidal]

Can someone please explain to me how a plasma ball works? I think I kind of get it. I get that the current flows through the gas inside of the ball because there is a large enough electrical potential difference between the two points. I'm not sure why the sparks follow you finger around the surface, but I suspect this is due to you fingers presence changing the potential at that point in space.

I'm also interested in how large is the power consumption for one of these things and what physical factors it depends on.

 

[Mk]

Why is it called "plasma?" Is it the type that is in the plasma tv, or is it just exited gas, but not quite plasma?

 

[Nickolas]

Why is it called "plasma?"

During the 1920's Irving Langmuir was studying various types of mercury-vapor discharges, and he noticed similarities in their structure - near the boundaries as well as in the main body of the discharge. While the region immediately adjacent to a wall or electrode was already called a "sheath," there was no name for the quasi-neutral stuff filling most of the discharge space. He decided to call it "plasma."
Nobody know why he called this name but maybe when he worked with anther person was sutdying about blood plasma at the General Electric Research Laboratory,he called this name.

In any case, it appears that the first published use of the term was in Langmuir's "Oscillations in Ionized Gases," published in 1928 in the Proceedings of the National Academy of Sciences