Highlights

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2021

Superconducting Magnetic Flux Pumps

High temperature superconducting (HTS) flux pumps are promising devices in order to inject large DC currents into the winding of superconducting machines or magnets in a contactless way. The superconducting dynamo, as a type of flux pump with simple structure and easy maintenance has become very popular during the recent years. Using the dynamos, employing troublesome brushes in HTS machines or bulky currents leads with high thermal losses will be no more required. The working mechanism of HTS dynamo in open- circuit mode and with transport current is complicated and not fully investigated yet, despite several explanations and models that have been proposed. Recently, we published the first three-dimensional (3D) computer modeling of HTS flux pumps, revealing the distribution of screening currents for the first time. We have also published our modelling results of the charging process of a superconducting coil, which approaches our research to superconducting power applications.

  • Ghabeli, A., Pardo, E., and Kapolka, M.: 3D modeling of a superconducting dynamo-type flux pump, Sci Rep. 11 (2021) 10296.
  • Ghabeli, A., Ainslie, M., Pardo, E., Queval, L., and Mataira, R.: Modeling the charging process of a coil by an HTS dynamo-type flux pump, Supercond. Sci Technol. 34 (2021) 084002.

Improvement of superconducting properties of thin films via laser annealing

In the framework of the EC project ARIES we have been studying the superconducting and structural properties of superconducting thin films annealed post-deposition with the help of the laser beam. Development of this technology is focused on optimization of the superconducting coating on the inner walls of the radiofrequency resonant cavities. Our experimental investigation confirmed that the laser post-annealing has a high potential for improvement of the superconducting properties of the deposited films. However, the laser beam intensity has to be carefully optimized, otherwise new surface defects can be created and degradation of the parameters is very likely to occur.

SEM micrographs of: a) surface of the Cu substrate, b) surface of the superconducting (Nb) thin film before the laser irradiation, c) – f) surface of the superconducting thin film after the laser irradiation (laser beam intensity increasing from c) to f)).
  • Ries, R., Seiler, E., Gömöry, F., Medvids, A., Onufrijevs, P., Pira, C., Chyhyrynets, E., Malyshev, O.B., and Valizadeh, R.: Improvement of the first flux entry field by laser post-treatment of the thin Nb film on Cu, Supercond. Sci Technol. 34 (2021) 065001.
  • Leith, S., Vogel, M., Fan, J., Seiler, E., Ries, R., and Jiang, X.: Superconducting NbN thin films for use in superconducting radio frequency cavities, Supercond. Sci Technol. 34 (2021) 025006.