Art student Need help with Plasma Toroid

[lovejdz]

*Hi there! I am an art student from a non-english speaking country therefore I have used GPT to translate. I apologise for any mistakes:)

My personal art project involves a Xenon Plasma Toroid and I am trying to make it myself with the support from a neon artist friend. However, I'm still in the process of learning about its physics and chemistry. If you could explain this to me in as simple terms as possible, I would greatly appreciate it!:)

Typically, the diameter of the Xenon Plasma Toroid globe is around 10cm, but I want to make one with a diameter exceeding 20cm. Here is some of my question.

(1)What are the advantages and disadvantages of using other inert gases compared to xenon? What problems might arise from using other types of gases, and how can I avoid them?

(2)How can I calculate the frequency of a Xenon Plasma Toroid with a diameter exceeding 20cm? What are the relationships between voltage, current, and resistance in the circuit for boosting and driving it, are there any formulas?

(3)As far as I know, the factors affecting electromagnetic force are the diameter of the coil and the number of turns in the coil. Once the circuit is determined, if I want to change the thickness of the wire or the diameter of the coil, what are the relationships between them and the number of turns in the coil, and how should I calculate them?

Thank you!

[alan sailer]

I have had some experience with plasma toroids.

1) using any gas other than xenon would not be easy if it even worked at all. I can tell you from direct experience that the xenon
globe must be backed under vacuum or a toroid may be impossible.

2) It's well worded question but I doubt anyone has built a 20cm plasma toroid. I doubt frequency
is the important parameter, power would be more applicable.

3) The number of turns that the drive circuit needs is determined by the tuning of the circuit. Thicker wire
should have less loss.

Steve Ward published an explanation of the type of oscillator used to generate toroids.

HFSSTC - The Classy Self Oscillator Steve Ward, Feb 2021.pdf

Finally, I am reminded of a talk by Richard Feynman given for a TV show. The interviewer asked Feynman
to give a simple explanation of magnetism. After a little thought Feynman replied that there was no such thing.

[toooldforthis]

Hello, I just built one of these myself so maybe I can answer some of your questions.

1: The color will vary. Other gasses and the addition of metals and maybe salts is possible. The globe may require re-tuning for different gasses as the plasma will probably have different properties that effect the Q of the resonant tank.

2: You can use LC resonant frequency formulas or online calculators to determine starting values for the resonant tank (https://www.omnicalculator.com/physics/resonant-frequency-lc). You want the frequency to be around 10MHz and the impedance (sqrt(L/C)) of the tank to be reasonable so the voltage on the high voltage node is reasonable. Starting values are something like 100pF and 2.5uH for example. One turn of copper tube at 16cm diameter will get you something like 0.6uH. You might want to try two turns for 2.4uH. See here: https://m0ukd.com/calculators/air-cored-inductor-calculator/

3: Diameter, turn count, and current effect the magnetic field strength. Diameter changes to the wire will not have a huge effect on the resonant frequency but will effect losses. Diameter changes to the coil will effect inductance which will cause different tuning of the LC tank. Use the above calculator to find reasonable values for turn count and diameter of the coil. Inductance probably needs to stay between something like 1uH and 3uH unless you want a drastically different impedance for some reason.

I have a YouTube video on this topic but it may not be of too much help if you don't understand spoken English.