The paper describes a high-temperature superconducting magnetic system (HTS SMS) to equip an experimental stand intended for neuron activity researches under constant and low-frequency magnetic fields up to 1 T. The design of the magnetic system together with its electromagnetic and cryogenic parameters is briefly discussed. The test results of the preliminary experiments conducted in liquid nitrogen at 77 K for two interchangeable magnets are given. The first magnet was manufactured in the form of a double pancake coil wound with 4 mm high HTS tape. The second magnet was made of pure copper wire with no frame and was impregnated with a thermally conducting epoxy resin. The advantages of the HTS pancake coil were demonstrated in comparison with the cryo-resistive solenoid. Low energy consumption of the HTS magnetic system will allow conducting continuous non-invasive monitoring of biological objects in a magnetic field.

Development of homopolar electric machines is a promising superconducting application. A homopolar motor with a 2G high-temperature superconducting (HTSC) magnetic system and copper disk rotor is designed at the NRC “Kurchatov Institute”. The advantages of such electric machines are considered. The liquid metal sliding contacts based on a gallium-indium-tin alloy are considered as a safe alternative to toxic mercury or NaK alloys. The homopolar motor controlling by a proportional-integral-differentiating (PID) algorithm is simulated and checked experimentally. The results of the preliminary tests of HTSC magnetic system and liquid metal contact are also reported.

The paper describes a high-temperature superconducting magnetic system (HTS SMS) to equip an experimental stand intended for neuron activity researches under constant and low-frequency magnetic fields up to 1 T. The design of the magnetic system together with its electromagnetic and cryogenic parameters is briefly discussed. The test results of the preliminary experiments conducted in liquid nitrogen at 77 K for two interchangeable magnets are given. The first magnet was manufactured in the form of a double pancake coil wound with 4 mm high HTS tape. The second magnet was made of pure copper wire with no frame and was impregnated with a thermally conducting epoxy resin. The advantages of the HTS pancake coil were demonstrated in comparison with the cryo-resistive solenoid. Low energy consumption of the HTS magnetic system will allow conducting continuous non-invasive monitoring of biological objects in a magnetic field.

In this work the design of a homopolar motor prototype is proposed. The magnetic system consists of a high temperature superconducting (HTS) stator and a disc rotor with liquid metal sliding electric contacts made of gallium indium tin alloy. The estimation of magnetic fields and torques is performed for the device. The possibility of using this motor as a servo actuator is considered. The results of the preliminary experimental attempts to control a singlepole motor based on permanent magnets by means of a proportional–integral–derivative (PID) algorithm are presented.

Разработаны и изготовлены источники магнитного поля для экспериментов по активации каналов нейронов. Разработаны криогенные магнитные системы, входящие в состав экспериментального исследовательского стенда для дистанционного регулирования экспрессии нейронов постоянным и низкочастотным (до 100 Гц) магнитными полями. При температуре жидкого азота (77 К) системы способны выдавать поле с величиной индукции ~0.5 Тл; при работе с переохлажденным жидким азотом (70–65 К) – выше 1 Тл. Подчеркнута актуальность применения в криомагнитной системе новейших и наиболее перспективных материалов на сегодняшний день – высокотемпературных сверхпроводников второго поколения.

High-gradient magnetic separator made a good showing at enrichment of low-magnetic ores. However, existing industrial facilities have large dimensions, low specific productivity and high energy costs. Laboratory prototype of high-gradient magnetic separator equipped with superconductor magnet system was developed, manufactured and tested at NRC “Kurchatov Institute”. The device is designed for enrichment of low-magnetic mineral resources, mostly oxidized ferruginous quartzites. The goal of development was both creation of next-generation of separators operating with high-power magnetic fields as well as further progress in applied superconductivity for industrial applications. This paper gives a brief description of the problem, as well as of the process of development, manufacturing and testing the superconducting magnet system. Overall design of the prototype is described, as well as design of collector matrices designed specifically for high-power magnetic field. Next is description of testing process with mineral raw materials obtained from a real industrial enrichment facility. Data on total iron percentage before and after the separation process at the prototype presented, as well as its basic performance characteristics. The results obtained in the course of the project fulfilment can be used in mining industry and metallurgy for manufacturing superconducting magnetic separators of new generation. Such separators will have many advantages comparing with regular separators (with resistive windings) as following: lower energy consumption and less weight, higher induction of the magnetic field in the working gap, possibility to use matrices with coefficient of filling by ferromagnetic precipitating elements at the level of 6-8% with large gaps for pulp passing, higher specific indices due to increased current density in the winding up to 50-100 A/mm2.

Magnetic field sources are developed and manufactured for experiments in order to activate neuron channels. The designed cryogenic magnetic systems are part of an experimental research stand for remotely controlling neuron expression by static and low-frequency (up to 100 Hz) magnetic fields. The devices are capable of producing an induction field value of ~0.5 T at the liquid nitrogen temperature (77 K); and when working with subcooled liquid nitrogen (70–65 K), the induction field value is above 1 T. The relevance of using the most promising materials—second-generation high temperature superconductors—in the cryomagnetic system is underlined.

The paper gives the results of the experiments with a model two-section REBCO solenoid cooled by either gaseous helium (GHe) or sub-cooled/solid nitrogen (SN2) in (50-77) K temperature range. The major cooling source was a single-stage cryocooler Sumitomo CH-110 with the cooling power of 175 W and 130 W at 77 K and 50 K respectively. The coil itself was not directly conduction cooled. We compare the time taken by both coolants to obtain the temperature of the magnet of about 50 K and the homogeneity of the temperature distribution within the cryostat. Test results for the coil operation in solid nitrogen together with the comparison of its critical properties in SN2 and GHe are also presented.

High gradient magnetic separation is a promising method for ores enrichment and industrial wastes recycling. The potential of separators based on resistive and permanent magnets is limited by the value of magnetic field and operational costs. LTS magnetic systems require liquid helium and complicated cryogenics. HTS magnets operated in solid nitrogen at 50 K can be a possible solution. In this study, we discuss the conceptual design of an HTS rotary separator prototype with the horizontally oriented rotor axis. The scheme allows to organize a continuous ore processing. The split magnet system consists of two 2G HTS coils on a soft-magnetic yoke with 50 mm room temperature gap. The paper gives the overall design of the magnetic system and the related cryogenic, together with the magnetic fields and forces calculations. The preliminary test results of the ReBCO coil in liquid and sub-cooled nitrogen are also presented.

The international project "NICA" (Nuclotron-based Ion Collider fAcility) is an accelerator complex which is under construction at the Joint Institute for Nuclear Research (Dubna, Russia). Basing on the NICA project demands NRC "Kurchatov Institute" (Moscow, Russia) designed and manufactured two trial 12 kA 1G current leads (CLs) intended for powering of the JINR superconducting magnets test bench. The main requirements for the CLs were: a reliable and robust design, usage of liquid nitrogen from the NICA cooling circuits as a resistive section coolant, low resistance joints, current ramp rates up to 10 kA/s and the total heat load to the 5 K end not exceeding 0.4 W/kA per one CL. An in-situ cold test of the trial 12 kA CLs held at JINR in 2015 demonstrated the operational reliability of our technological approaches. Following the successful test results the serial production of 20 pairs of 10.5 kA HTS CLs with very few design updates for the accelerator powering started. The first 10 pairs were fabricated, tested and shipped to JINR as a part of the NICA commissioning framework in June 2017. All the CLs fulfilled the acceptance test requirements. The production of the remaining 10 pairs is to be finished in 2018. The paper gives an overview of the 12 kA and 10.5 kA HTS CLs' design, discusses their thermal, magnetic and electrical characteristics and presents the acceptance tests results. We also compare our CLs with earlier works by other groups in the context of HTS stack-and-soldering technique, joints' resistances, relative heat loads into the cryogenic environment etc.

High gradient magnetic separation is an effective method for ores enrichment and industrial wastes recycling (including radioactive wastes). The possibilities of separators based on resistive and permanent magnets are limited due to relatively low value of magnetic induction and rather high energy consumption. LTS magnetic systems require liquid helium and complicated cryogenics which can be costly and not always optimal for use at industrial facilities. High-temperature superconductors operated in liquid, sub-cooled and solid nitrogen and equipped with cryocoolers are promising materials that can help expanding industrial application of superconducting devices. In this study, we discuss the design of an HTS rotary separator prototype with the horizontally oriented rotor axis together with the magnetic fields and forces calculations that define prototype working parameters; overall design of HTS-2G coils and preliminary test results of the said coils at different operating temperatures.

A high gradient magnetic (HGM) separator prototype with the 2nd generation high temperature superconducting (2G HTS) magnetic system operated in sub-cooled nitrogen is presently under development at NRC "Kurchatov Institute" (Moscow, Russia). The main goal of the project is an attempt to shift away from the complicated liquid helium cryostats towards simple cryocooler-based nitrogen cryogenics as much more convenient for HGM separators industrial applications. Using of commercial HTS tapes allows to get a sufficient level of magnetic fields and extraction forces with low energy consumption. The expected operational parameters of the device are 1.2-1.5 T in the empty operational gap and up to 3 T on the ferromagnetic filters. In this paper we briefly describe the design of the HTS rotary separator prototype with the horizontally oriented rotor axis and propose different types of ferromagnetic filters intended for weakly magnetic ores enrichment.

New fusion devices are being discussed in Russia. One item is a superconducting magnet development for the demonstration hybrid facility-fusion neutron source based on a tokamak concept with the conventional aspect ratio ~3. The magnetic parameters of this device are planned to be: 5 Ton the plasma axis and about 12 Ton the high field side of the toroidal field coils. Because of a high neutron flow and a thick shielding, the space remained for the inner legs of the toroidal field coil is very tight. Therefore, a very high current density is needed for the windings. Several magnet designs have been addressed up to now with required engineering critical current density sim 1000 A/mm 2 at least. In this review, we present conceptual design of the magnet system, necessary strand parameters, and their irradiation properties. Few possible designs of the toroidal field, conductors are discussed. The R&D of efficient HTS current leads to be used for fusion machines are discussed as well.

A pair of hybrid current leads (brass + stacked & soldered ReBCO tapes) rated for 12 kA in steady state and for up to 18 kik at pulsed over current conditions was designed, developed and tested at NRC "Kurchatov Institute" (NRC "KI"). During the experiment at LN2 temperature, the current leads (CLs) were successfully charged with 18 kA at 100 A/s ramp rate. To date, as far as we know, this is the highest current capacity achieved for 2G HTS current leads. The feasibility of "stack-and-soldering technique" for 10 kA+ class coated conductor CLs for accelerators and fusion was demonstrated. This paper gives an overview of the leads design and presents the preliminary test results. Detailed studies of magnetic properties and current sharing process for the stacked and staggered HTS joints are also reported. (C) 2017 Elsevier Ltd. All rights reserved.

The feasibility of creating high-current leads on the basis of second-generation (2G) high-temperature superconductors (HTSs) was demonstrated. A method for graded soldering of 2G HTS tape stacks is proposed. It allows one to avoid negative effects that are related to an inhomogeneous current sharing between parallel HTS conductors. A prototype of HTS-coated current leads (CLs) was designed, manufactured, and tested; its critical current exceeds 18 kА. Prototypes of HTS CLs for the superconducting magnetic system of the Nuclotron accelerator (a part of the NICA collider) with an operating current of 6 kA were developed, manufactured, and tested in liquid helium (the overcurrent was 9 kA).