Reference : Magneto-thermal phenomena in bulk high temperature superconductors subjected to appli...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Engineering, computing & technology : Electrical & electronics engineering
http://hdl.handle.net/2268/55974
Magneto-thermal phenomena in bulk high temperature superconductors subjected to applied AC magnetic fields
English
Vanderbemden, Philippe mailto [Université de Liège - ULg > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Capteurs et systèmes de mesures électriques >]
Laurent, Philippe [Université de Liège - ULg > Dép. d'électric., électron. et informat. (Inst.Montefiore) > Electronique, microsystèmes, mesures et instrumentation >]
Fagnard, Jean-François [Ecole Royale Militaire (Belgique) - ERM > > > >]
Ausloos, Marcel [Université de Liège - ULg > Département de physique > Département de physique >]
Hari Babu, N. [Brunel University, West London > Brunel Centre for Advanced Solidification Technology (BCAST) > > >]
Cardwell, D. A. [University of Cambridge > Bulk Superconductivity Group, Engineering Department > > >]
2010
Superconductor Science and Technology
Institute of Physics
23
075006
Yes (verified by ORBi)
International
0953-2048
Bristol
United Kingdom
[en] magnetic properties ; critical currents ; thermal properties
[en] In the present work we study, both theoretically and experimentally, the temperature increase in
a bulk high temperature superconductor subjected to applied AC magnetic fields of large
amplitude. We calculate analytically the equilibrium temperatures of the bulk sample as a
function of the experimental parameters using a simple critical state model for an infinitely long
type-II superconducting slab or cylinder. The results show the existence of a limit heat transfer
coefficient (AUlim) separating two thermal regimes with different characteristics. The
theoretical analysis predicts a ‘forbidden’ temperature window within which the temperature of
the superconductor can never stabilize when the heat transfer coefficient is small. In addition,
we determine analytical expressions for two threshold fields Htr1 and Htr2 characterizing the
importance of magneto-thermal effects and show that a thermal runaway always occurs when
the field amplitude is larger than Htr2. The theoretical predictions of the temperature evolution
of the bulk sample during a self-heating process agree well with the experimental data. The
simple analytical study presented in this paper enables order of magnitude thermal effects to be
estimated for simple superconductor geometries under applied AC magnetic fields and can be
used to predict the influence of experimental parameters on the self-heating characteristics of
bulk type-II superconductors.
Services Universitaires Pour la Recherche et les Applications Technologiques de Matériaux Électro-Céramiques, Composites, Supraconducteurs - SUPRATECS
Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS ; Royal Military Academy of Belgium ; Université de Liège
Researchers ; Professionals
http://hdl.handle.net/2268/55974
10.1088/0953-2048/23/7/075006
http://iopscience.iop.org/0953-2048/23/7/075006

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