Estimation of generated heat in pulse field magnetizing for SmBaCuO bulk superconductor

Fujishiro, Hiroyuki; Yokoyama, K.; Kaneyama, Masahiko; Oka, Tetsuo; Noto, Kōshichi

doi:10.1016/j.physc.2004.01.083

Cited by 31 publications

(29 citation statements)

References 6 publications

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“…In practice, a detailed understanding of these effects requires specific experimental investigations. Fujishiro et al successfully measured the temperature rise and the field distribution during pulse field magnetizing of bulk superconductors [12], [13]. Tsukamoto et al have calculated and measured the temperature distribution at the surface of a permanently magnetized bulk superconductor after the application of an external ac magnetic field [14].…”

mentioning

confidence: 99%

Measurements of Thermal Effects in a Bulk YBCO Single Domain Superconductor Submitted to a Variable Magnetic Field

Laurent

Vanderbemden

Meslin

et al. 2007

IEEE Trans. Appl. Supercond.

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Abstract-When YBCO single domains are subjected to a variable magnetic field, the motion of vortices may give rise to a significant temperature increase and a degradation of the superconducting properties. We have experimentally investigated such effects in bulk melt-processed YBCO single domains. Several temperature sensors, a pick-up coil and two Hall probes were placed against the surface of a monolithic bulk YBCO pellet. Data were simultaneously recorded during the application of ac magnetic fields of various amplitudes, either with or without a pre-existing dc trapped flux. The measurement results agree well with to those obtained by numerical modeling. It was also found that a superimposed dc magnetic moment reduces the temperature increase caused by the ac magnetic field.Index Terms-High-temperature superconductors, magnetic variables measurement, thermal variables measurement.

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confidence: 99%

Measurements of Thermal Effects in a Bulk YBCO Single Domain Superconductor Submitted to a Variable Magnetic Field

Laurent

Vanderbemden

Meslin

et al. 2007

IEEE Trans. Appl. Supercond.

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“…Three magnetic pulses (Nos. [1][2][3] with nearly the same amplitude B ex from 3 to 6.5 T were applied sequentially after re-cooling to 40 K. for the No. 1 pulse in "set B" for each t, which was re-plotted using Fig.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Furthermore, we estimated the generated heat Q during PFM by use of the temperature rise ∆T and the specific heat C of the bulk [3]. Taking these results into consideration, we proposed a new PFM method named a modified multi-pulse technique with stepwise cooling (MMPSC) and attained 5.2 T on the GdBaCuO bulk 45 mm in diameter at 30 K, which is a record high B T P value to date [4].…”

Section: Introductionmentioning

confidence: 99%

Temperature measurements in small holes drilled in superconducting bulk during pulsed field magnetization

Fujishiro

Naito

Furuta

et al. 2010

Physica C: Superconductivity and its Applications

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The time dependence of the temperatures T(z, t) has been measured along the thickness direction z in several drilled holes in a superconducting bulk during pulsed field magnetization (PFM) and the heat generation and heat transfer in the bulk have been discussed. In the previous paper (Supercond. Sci. Technol. 19 (2006) S540), we calculated the T(z, t) profiles in the bulk by solving a three-dimensional heat-diffusion equation to reproduce the measured T(t) on the bulk surface; the heat generation took place adiabatically and the calculated T(z, t) was isothermal along the z direction. In this study, the measured T(z, t) at the top surface was higher than that at the bottom surface just after the pulse field application at t<0.5 s, and then became isothermal with increasing time. These results suggest that the magnetic flux intrudes inhomogeneously into the bulk from the edge of the top surface and the periphery at the early stage. The ACCEPTED MANUSCRIPTinhomogeneous magnetic flux intrusion and the flux trap during PFM change depending on the strength of the pulsed field and the pulse number in the successive pulse field application. (184 words)

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“…For example, temperature rises of up to 30 K have been observed, depending on the initial temperature, the amplitude and duration of the pulsed field during the magnetization of bulk YBCO [29]. Although much smaller field sweep rates are involved, the second situation (magnetization during a FC or after a ZFC procedure), can induce temperature rises up to ~ 7 K [19].…”

Section: Introductionmentioning

confidence: 99%

Magneto-thermal phenomena in bulk high temperature superconductors subjected to applied AC magnetic fields

Vanderbemden¹,

Laurent²,

Fagnard³

et al. 2010

Supercond. Sci. Technol.

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Abstract.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 (AU lim ) 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 an analytical expression of two threshold fields H tr1 and H tr2 characterizing the importance of magneto-thermal effects and show that a thermal runaway always occurs when the field amplitude is larger than H tr2 . 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.

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Estimation of generated heat in pulse field magnetizing for SmBaCuO bulk superconductor

Cited by 31 publications

References 6 publications

Measurements of Thermal Effects in a Bulk YBCO Single Domain Superconductor Submitted to a Variable Magnetic Field

Measurements of Thermal Effects in a Bulk YBCO Single Domain Superconductor Submitted to a Variable Magnetic Field

Temperature measurements in small holes drilled in superconducting bulk during pulsed field magnetization

Magneto-thermal phenomena in bulk high temperature superconductors subjected to applied AC magnetic fields

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