# Electric Discharge acts as in LC Circuits?

For the most part, do electric discharges behave as tank circuits? For example, an air capacitor; when the electric field causes the air to breakdown and conduct, will the discharge alternate at a frequency defined by the inductance of the plasma channel and the capacitance of the capacitor?

berkeman
Mentor
For the most part, do electric discharges behave as tank circuits? For example, an air capacitor; when the electric field causes the air to breakdown and conduct, will the discharge alternate at a frequency defined by the inductance of the plasma channel and the capacitance of the capacitor?
I don't think so. Many discharges are DC in nature...

https://en.wikipedia.org/wiki/Electric_arc

Wait, Ive come to understand that discharges oscillate. For example, lightning.

berkeman
Mentor
Wait, Ive come to understand that discharges oscillate. For example, lightning.
Can you post a technical reference that describes that?

Oh wow, just found where I learned that from. Here you go, is quite old:
Discharge Oscillatory The sudden or disruptive discharge of a static condenser such as a Leyden jar or of many other charged conductors is oscillatory in character The direction of the currents rapidly changes so that the discharge is really an alternating current of excessively short total duration The discharge sends electro magnetic waves through the ether which are exactly analogous to those of light but of too long period to affect the eye.

Even though the author is referring to the ether, doesn't mean he is wrong about the alternating nature of disruptive discharges. I had a hard time finding anything else. Can you post a technical reference that describes discharges to be dc?

berkeman
Mentor
Yoiks, that is really old! Can you read some more modern explanations of lightning? It's mainly a DC discharge, but there are certainly high-frequency components due to discontinuities in the discharge.

Samson4
Yeah haha I know. Can't believe I held on to that information for so long.

I don't understand why it wouldn't oscillate. The only difference between a electric discharge and a tank circuit is the location of the inductor. Unless the magnetic fields produced by plasma channels do not exhibit the same resistance to change that magnetic fields around coils do, shouldn't it oscillate? Where is my understanding going foul?

nasu
Gold Member
Yeah haha I know. Can't believe I held on to that information for so long.

I don't understand why it wouldn't oscillate. The only difference between a electric discharge and a tank circuit is the location of the inductor. Unless the magnetic fields produced by plasma channels do not exhibit the same resistance to change that magnetic fields around coils do, shouldn't it oscillate? Where is my understanding going foul?
For one, you forget the resistive component. You have oscillations only when the damping is subcritical.

Samson4
Thank you both for your responses.