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

Hi, guys, quick question for the more technically-minded among you. As a novice, being able to identify certain components as active or passive still eludes me. I know that tubes and semiconductors are considered active because they apparently "use electricity to control electricity" or because they require a power supply to operate. I know that resistors, capacitors, and inductors are considered passive.

So what about electric arcs and spark gaps? Is the discharge component in an antique spark-gap transmitter or a Tesla coil an active component? What if an LC circuit were to be placed across an electric arc in, say, a carbon lamp -- would the arc be considered an active component in that case?

Thanks for any help with this!