Undergrad Colors in a plasma globe

[Orthoceras]

TL;DR

Why are the streamers blue while the pads at both ends are orange, in a plasma globe?

I have a common plasma globe with blue streamers and orange pads at both ends. The orange light is emitted by neon and the blue light is presumably emitted by argon and xenon.
Why are the streamers blue while the pads at both ends are orange? A plasma globe's electric field is strong near the central electrode, decreasing with distance, so I would not expect the orange color at both ends.

 

[renormalize]

TL;DR: Why are the streamers blue while the pads at both ends are orange, in a plasma globe?

How much research did you attempt before posting your question? I ask because at or near the top of a simple google search for "plasma globe colors" is the Wikipedia link https://en.wikipedia.org/wiki/Plasma_globe which states:

"Plasma balls are driven by high-frequency (approximately 35 kHz) alternating current at 2–5 kV... The radio-frequency energy from the transformer is transmitted into the gas within the ball through an electrode at its center... Plasma filaments extend from the inner electrode to the outer glass insulator, giving the appearance of moving tendrils of colored light within the volume of the ball (see corona discharge and electric glow discharge)."

"Some balls have a control knob that varies the amount of power going to the center electrode. At the very lowest setting that will light or "strike" the ball, a single tendril is made. This single tendril's plasma channel engages enough space to transmit this lowest striking energy to the outside world through the glass of the ball. As the power is increased, this single channel's capacity is overwhelmed and a second channel forms, then a third, and so on. The tendrils each compete for a footprint on the inner orb as well. The energies flowing through these are all of the same polarity, so they repel each other as like charges: a thin dark boundary surrounds each footprint on the inner electrode."

"The ball is prepared by pumping out as much air as is practical. The ball is then backfilled with neon to a pressure similar to one atmosphere. If the radio-frequency power is turned on, if the ball is "struck" or "lit", now, the whole ball will glow a diffuse red. If a little argon is added, the filaments will form. If a very small amount of xenon is added, the "flowers" will bloom at the ends of the filaments."

So ultimately it is the energy variations within the currents flowing through the plasma in different regions that excite the various noble gasses to glow with their characteristic colors in those regions.

 

[Charles Link]

The OP may find it of interest that as the degree of ionization in a plasma increases, basically as the current density rises, the electrical resistance decreases. That way, once a path, i.e. an arc, through the plasma is established, it tends to stay there with some stability. This is what makes up the filaments.