Plasma extraction microcavity plasma device and method

A preferred embodiment plasma extraction microcavity plasma device generates a spatially-confined plasma in a gas or vapor, or gas and vapor mixture, including, for example, atmospheric pressure air. A microcavity plasma device is excited by a potential applied between excitation electrodes of the microcavity plasma device, and a probe electrode proximate the microcavity is maintained at the potential of one of the electrodes, extracts plasma from the microcavity plasma device. In preferred embodiments, the excitation electrodes of the microcavity plasma device are isolated from the plasma by dielectric, and time-varying (AC, RF, bipolar or pulsed DC, etc.) potential excites a plasma that is then extracted by the probe electrode. In alternate embodiments, the microcavity plasma device has an excitation electrode that contacts the plasma. A DC potential excites a plasma that is then extracted by the probe electrode.