The Symposium on Electromagnetic Processing of Materials (EPM) was organized in the beginning of the 1990s in Japan in cooperation with France. EPM applies various electromagnetic phenomena to materials processing. In the early stages of EPM, it was mainly applied to steel-making processes like heating, melting, stirring, flow control and so on. However, its application has been extended recently to nonferrous metals like aluminum, and even to nonmagnetic materials by the use of DC superconducting magnets. In the present paper, examples of EPM are shown and the applicability of superconducting magnets to conventional EPM is investigated. If AC superconducting magnets are applied to conventional EPM, the limit of EPM due to the weakness of the magnetic field will be broken and a new stage of EPM applications will be opened.
This report describes the development of low vibration cooling systems with pulse tube (PT) cryocoolers. Generally, PT cryocoolers have the merit of lower vibration than GM cryocoolers. However, the cooling systems for a cryogenic laser interferometor observatory (CLIO), which is a gravitational wave detector, require sufficiently lower operational vibration than that of a commercial PT cryocooler. The required specification for vibration amplitude on cold stages is less than ±1 μm. Therefore, during development of the low vibration cooling systems for CLIO, we introduced advanced countermeasures for commercial PT cryocoolers. The cooling performance and the vibration amplitude were evaluated. Results revealed that, 4 K and 80 K PT cooling systems, which have a vibration amplitude of less than ±1 μm and respective cooling performances of 4.5 K at a heat load of 0.5 W and 70 K at a heat load of 50 W, were developed successfully.