Electric arcs and spark gaps: Are they active or passive devices?

An electric arc shunted across an LC circuit (in, say, a carbon arc lamp) would produce an oscillator. I don't know of any passive electronic oscillators, so would the arc be considered an active device in this case?

What about the spark gap in Tesla coils? Active or passive? The vacuum tube in tube-based Tesla coils? The semiconductor in solid-state Tesla coils? Are any of these considered active or are they in fact passive?

Thanks for any help with this!

Hi,

An active device is any type of circuit component with the ability to electrically control electron flow (electricity controlling electricity). In order for a circuit to be properly called electronic, it must contain at least one active device. Components incapable of controlling current by means of another electrical signal are called passive devices. Resistors, capacitors, inductors, transformers, and even diodes are all considered passive devices. Active devices include, but are not limited to, vacuum tubes, transistors, silicon-controlled rectifiers (SCRs), and TRIACs.

I would say, it is a passive component.