摘要 |
<p>A system and method for maintaining a plasma in a plasma region, by supplying RF power at a fundamental frequency to the plasma region together with a gas in order to create an RF electromagnetic field which interacts with the gas to create a plasma that contains electromagnetic energy components at frequencies that are harmonics of the fundamental frequency. The components at frequencies that are harmonics of the fundamental frequency are removed from the plasma by placing a body of an RF absorber material in energy receiving communication with the plasma, the body having a frequency dependent attenuation characteristic such that the body attenuates electrical energy at frequencies higher than the fundamental frequency more strongly than energy at the fundamental frequency.</p> |