THERMOACOUSTIC RESONATOR - Thermoacoustic Cycle engine: "A Thermoacoustic Cycle engine is typically comprised of a resonant cavity in the approximate shape of a cylinder, tube or torus, in which a working fluid resides, and in which an applied difference in thermal potential, across internal isothermal heat exchangers that are separated by a regenerative heat exchanger (stack) and spaced along the length of the resonant cavity by a nominal wavelength or fraction thereof, produce and amplify acoustic waves which transport thermal energy from one heat exchanger to another, and maintain a state of oscillation, or periodic thermal and acoustic flux, in the working fluid. To extract useful work from the engine, the oscillating pressure component can be applied to a mechanical member, such as a piston, in order to perform reciprocating work, and thereby used to perform tasks such as pumping fluids or generating electrical energy. The maxima, or peak pressure points in the traveling thermoacoustic wave train, also transport thermal energy in accordance with the pressure-temperature relationship in a gas, as described in Charles Law, and this property can be employed in a reverse entropy cycle to produce refrigeration."