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thadman 8th April 2010 05:21 AM

Holding current for stable plasma
I'm interested in building a plasma loudspeaker using a 1kW amplitude modulated RF amplifier. The amplifier will modulate the output of a 27Mhz RLC circuit which is connected in series between two Tungsten electrodes (opposite polarity). I believe if a potential of 30kV/cm is placed between the electrodes, dielectric breakdown of the air will occur and plasma will form. Electricity will then be conducted through the plasma. If we modulate the 27Mhz resonance, we can vary the size of the plasma rapidly to produce sound in the audio bandwidth. We desire a stable plasma, which may allow us to assume a Maxwellian distribution.

If we directed helium gas towards the electrodes, how much would this effect dielectric breakdown? How could I calculate the distribution of air and helium? Would it be possible to calculate ozone production?

For a stable plasma to be assumed, a "holding current" must be maintained. How can I calculate this? The holding current will place a constraint on the widest possible air gap that will support a stable plasma if I have a limited amount of power.

Is infinite electrical conductivity a poor assumption for the plasma?

How can I calculate the pressure field (ie acoustic field) created by modulating the resonance by varying the current? How can I calculate the percentage of electrical energy that is converted to acoustic energy?


PMA 8th April 2010 05:48 AM

Yo are asking good questions ;), but you would rather need practical experience with plasma.

Best regards,

okk 11th July 2010 04:40 AM

A self-oscillator (positive RF amp) will realize a stable plasma flame.
A lot of diyer have done such things.

PedroDaGr8 11th July 2010 05:01 AM

I don't have much help but this reminded me of my analytical chemistry professor back in undergrad. He used to brag about how during christmas time they used to hook up their ICP (Inductively Coupled Plasma) to a casette player and blast christmas songs that could be heard through the whole building. He was a bit kooky but a brilliant man, we called the class how to take over the world via chemistry.

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