parallel arrangements to create a pump system the pump may be pre biased to make its response more linear by either mechanical or magnetic biasing a permanent magnet may be used to magnetically bias the pump and create an 34 at rest 34 initial extension of the magnetostrictive element similarly a spring may be used to mechanically load the magnetostrictive element a controller is used to detect feedback signals from pressure and pump displacement transducers and thereby provide active control of the pump or pump system it is especially useful for high performance liquid chromatography application_number US 50947295 A description in accordance with this invention a pump is provided which utilizes a magnetostrictive element and a working fluid chamber the chamber has a compliant surface which is contacted by an extension that moves with a working end of the magnetostrictive element contained within the chamber is a working fluid and a bellows which is surrounded by the working fluid the bellows defines a volume into and out of which flows a fluid to be pumped the fluid to be pumped is isolated from the working fluid by the walls of the bellows as described in more detail hereinafter a plurality of these pumps may be arranged to work in concert with one another as part of a pump system a controller which controls the generation of a magnetic field to drive the magnetostrictive element can be provided to regulate flow rate and pressure of the fluid to be pumped the controller is preferably a high speed controller such as a digital signal processor dsp.