Why Does High Frequency Corona Tend to Orient Vertically?

[pager48]

I noticed high frequency (greater than 800khz) corona tends to orientate vertically as if it were a flame with a strong air blower beneath it regardless of electrode positioning. This is not the case for DC and low frequency AC corona. Is there a reason why high frequency corona orientates vertically? Whats the typical temperature of a tesla coil high frequency corona?

 

[anorlunda]

That's an interesting question. I tried but failed, to find an answer to your simple question about temperature.

The fields near the conductor acclerate and move the ions and electrons nearby, thus causing heating. There is a net current in the corona, hence transmission lines see corona as a power loss.

Calculations for plasmas are very complex and probably not what you are looking for.

One thing I found while searching was the following tidbit that I didn't know before. It may be related to the flame-like behavior you ask about.

Ionized gases produced in a corona discharge are accelerated by the electric field, producing a movement of gas or electrical wind. The air movement associated with a discharge current of a few hundred microamperes can blow out a small candle flame within about 1 cm of a discharge point. A pinwheel, with radial metal spokes and pointed tips bent to point along the circumference of a circle, can be made to rotate if energized by a corona discharge; the rotation is due to differential electric attraction between the metal spokes and the space chargeshield region that surrounds the tips