One explanation states that the surface area differential between anode and cathode
is what contributes to the plasma ball's capability to produce the effects seen.
The placement of a magnetic or electrostatic field in 'specific' orientation to a plasma ball causes the replication of several features seen on the sun, to include: changes in tufting, concentration and separation of filaments and hexagonal re-arrangement of filaments at one end in the least (which may provide clues to hexagonal polar formation on planetary bodies).
On the far side of globe is an example of hexagonal arrangemnt seen as the boundary area between tendrill groups.
Proximity of the globe to an electrostatic field also increases tufting on central sphere.
On the center sphere you can see why hexagonal formation are a natural result due to the angle formed by three adjacent circular regions. This can be seen at either end of the filaments under the right conditions.
These images attempt to show changes to the central sphere as the conductive condition of the globe is changed by a surrounding field, my cupped hands.
_ __ _
The filaments are not the actual appearance in either photo except in a relative sense.
The info i've found so far is written up for alternating current.
At this time the interior sphere is the principle point of attention in my thought since the bright filamenary characteristic is a 'forced effect', from what i've rhed, . From observation, it changes to a diffuse characteristic when the globe is surrounded almost entirely by cupped hands. At this time the central sphere becomes entirely covered with tufting, if i can call it that. The process behind bright filaments seems to depend on AC and heat, for this device but i would not be surprised to hear of other ways to accomplish charge accumulation and release. In this case it is from the central plate to another plate but under condition found at solar scale other factors may take over where ac itsn't available, if in fact it doesn't occur naturally, but i don't know for sure about all the details involved so I hope other have some input on how to accomplish further investigation.