Flux-pumped ultra-high current magnets

Lead Research Organisation: University of Cambridge
Department Name: Engineering

Abstract

The project is primarily carried out at Cambridge University by the research team led by Dr Coombs. The research is constituted to address fundamental underpinning research into the development of ultra-high field magnets that will help to advance research into novel materials and to further understand existing ones.

Superconducting technology can be used for improving the efficiency and performance of advanced research into exotic states of matter. Although persistent magnetic fields as high as 45 T have been produced using hybrid copper and superconducting magnets they are bulky and expensive to run. Achieving fields greater than 45T can be achieved as transients but the only way to produce such high fields in persistent mode is with HTS. This project will facilitate the provision of the high currents which are required to achieve high fields.

Flux pumped ultra-high current magnets have the potential to produce fields which surpass the nearly 20 year old record of 45 T in a DC field Bitter magnet in a relatively cost effective manner. These higher fields will undoubtedly require superconducting cables capable of carrying thousands of amps and the means to deliver those very high currents. Current leads could be used but at currents in the 10s of thousands of amps they represent a very high cost and heating overhead. Higher currents mean lower conductor cost, lower magnet inductances shorter charging times and lower quench voltages. Flux pump technology and the latest dynamic bridge switching method will be key to providing these high currents with minimal heat loads and minimal infrastructure in comparison to expensive high-current power supplies and warm-to-cold current leads. The resultant effect is that the purchase and running costs of high-field magnets will decrease substantially. Crucially also infra-structure costs will be slashed.

Planned Impact

The ultimate aim of this project is to make high field magnets accessible to a greater range of researchers by reducing capital, infrastructure and running costs.

It is expected that using the output from this project we will be able to surpass the nearly 20 year old record of 45 T in a DC field Bitter magnet in a relatively cost effective manner. These higher fields will undoubtedly require a superconducting cable capable of carrying up to 20,000 Amps to reduce the magnet inductance - by as much as four orders of magnitude - in order to reduce cost and to manage the charging and quench voltages. Flux pump technology and the latest dynamic bridge switching method will be key to providing these high currents with minimal heat loads and minimal infrastructure in comparison to expensive high-current power supplies and warm-to-cold current leads. The resultant effect is that the purchase and running costs of high-field magnets will decrease substantially. Crucially also infra-structure costs will be slashed. A flux pumped HTS magnet does not require MW power supplies neither does it require copious amounts of water cooling to dissipate the waste heat. Thus it is realistic to expect HTS flux pumped magnets to be available which could be installed in any UK (or international) university enabling a radical sea change in the use of high field magnets to support research. Further down the line it is conceivable that HTS flux pumped magnets could enable the creation of practical fusion devices a goal which has eluded us for many years.

Publications

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