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Normal zone propagation in a YBCO superconductor at 4.2 K. and above

Hesselink, A.R. (2015) Normal zone propagation in a YBCO superconductor at 4.2 K. and above.

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Abstract:The normal zone propagation velocity and minimum quench energy of a 2-mm wide YBCO superconductin 'coated conductor' tape are investigated at temperatures between 4.2 and 29 K, at three di�erent magnetic �eld strengths and at varying operating currents. Con�rming earlier observations on a wider tape at higher temperatures and in contrast to the simplest and most widely used theoretical model, it was found that the normal zone propagation velocity predominately depends on the current and hardly so on temperature or magnetic �eld. In agreement with theoretical predictions, the minimum quench energy was found to depend on both temperature and current, while the collected data do not allow to make a reliable conclusion about its magnetic �eld dependence. A more sophisticated analytical and a numerical model con�rm the temperature independence of the normal zone propagation velocity for temperatures below 25 K. Comparison between the absolute value of the normal zone propagation velocity show a quantitative di�erence of 50% between the 2-mm and 4-mm wide sample. Although several likely causes were investigated, this di�erence remains as yet unexplained.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:33 physics
Programme:Applied Physics MSc (60436)
Link to this item:http://purl.utwente.nl/essays/67101
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