Thermomechanical pumps for cooling with forced flow of superfluid helium

Superfluid helium has excellent features for cooling of superconducting magnets. This is due to its extraordinarily good thermal conductivity and due to its unusual flow behavior. Some applications need cooling by forced convection. Different methods for producing such convections either by use of the external compressor or by additional pumps in secondary loops are considered. Special attention is drawn to the possibility of using the thermomechanical effect (fountain effect) for driving such convection. The design of such pumps will be described and it will be discussed how they can be applied reasonably. (author)