A Newly Developed Pulse-Type Microampere Magnetic Flux Pump
A newly pulse-type microampere magnetic flux pump has been developed. This flux pump is used to compensate the decay of magnetic field in the high temperature superconducting (HTS) magnet coils. The superconducting joint resistance and lower n-index value induce the HTS coils could not operate in a persistent current mode. But using a flux pump would solve the problems. This paper presents the structure design and the basic principle of a newly developed pulse-type microampere magnetic flux pump. The developed flux pump has a simple structure. It is estimated that it will have low ripple and exact compensation for current. The current running in the flux pump is controlled by a pulse which is under the commands of the computer. In this way, the direction of the traveling field is easy to control. The working process of the flux pump is investigated in detail and some experiments have been performed. The results show that the new type flux pump can be regarded as a power supply providing for a persistent current because of the high pumping current. The developed flux pump is expected to be applied to the HTS magnetic resonance imaging (MRI) magnet system and nuclear magnetic resonance (NMR) magnet system.