Abstract: A compressor with no moving parts in the traditional sense having a housing having an inlet end allowing a low pressure fluid to enter and an outlet end allowing a high pressure fluid to exit. Within the compressor housing is at least one compression stage to increase the pressure of the fluid within the housing. The compression stage has a quantity of magnetic powder within the housing, is supported by a screen that allows passage of the fluid, and a coil for selectively providing a magnetic field across the magnetic powder such that when the magnetic field is not present the individual particles of the powder are separated allowing the fluid to flow through the powder and when the magnetic field is present the individual particles of the powder pack together causing the powder mass to expand preventing the fluid from flowing through the powder and causing a pressure pulse to compress the fluid.

Abstract: A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications comprised of a compressor section (10) centrally aligned end to end with an expansion section (12) and respectively including a reciprocating compressor piston (14) and displacer (16) radially suspended in interconnecting cylindrical housings (18, 20) by active magnetic bearings (26, 28, 30, 32) and having adjacent reduced clearance regions (82, 84, 108) so as to be in non-contacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston (14) and displacer (16) are reciprocated in their housings (18, 20) by linear drive motors (48, 52) to vary the volume of respectively adjacent compression and expansion spaces (44, 46) which contain a gaseous working fluid and a thermal regenerator (95) to effect Stirling cycle cryogenic cooling.