Normal zone acceleration: a new model to describe the quench process in superconductors with changing current
✍ Scribed by N.A. Buznikov; A.A. Pukhov; A.L. Rakhmanov
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 798 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0011-2275
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✦ Synopsis
Quench propagation is studied in a superconductor with changing transport current I(t) placed in a varying magnetic field B(t). It is shown that the normal zone propagation velocity v increases and the quench energy ec decreases with an increase in the rate of change of transport current / and magnetic field B. Such normal zone acceleration arises due to interaction between the propagating normal zone and thermomagnetic instability induced by varying / and B. This effect takes place both for increasing and decreasing currents and changes the values of v and ec by several orders of magnitude. The analytical and numerical dependences v(I, B) and ec(/, B) are found. Analytical expressions for v and ec which are valid for a wide range of/, B values are obtained and compared with both experimental and numerical data. Good agreement is observed. The obtained results may be of importance for understanding the abnormally fast quench propagation in pulsed magnet systems (such as SMES), sectional magnets, thermally controlled switches and superconducting a.c. devices.