Patent ID: 8232728

Claim:
Method for igniting and generating a microwave plasma by use of an apparatus comprising a microwave-limiting hollow structure containing gas, a microwave generator for supplying microwave energy via a microwave coupling into the microwave-limiting hollow structure, and a resonant ignition structure arranged within the microwave-limiting hollow structure, the method comprising: supplying microwaves via the microwave coupling into the wave-limiting hollow structure containing gas thereby to form a microwave field which generates a plasma and the resonant ignition structure building a resonance field strength which is sufficiently high for igniting the plasma even when greater power is not supplied, whereby the plasma is ignited and energy is supplied from the microwave field to the plasma so that the plasma is expanded and diffused, and driving of the plasma through the resonant ignition structure does not occur because the supplying to the plasma of energy from the microwave field provides inherent protection of the resonant ignition structure due to autoregulating transition between a plasma ignition phase and a plasma maintenance phase.