Dependence of thermomagnetic instability on the strong nonlinear E-J models in superconducting films
Dependence of thermomagnetic instability on the strong nonlinear E-J models in superconducting films
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DOI：
10.7498/aps.71.20220285
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Xue Cun
中科院分区：
文献类型：
--
作者：
Wang Yao;Jiang Lu;Zhou You-He;Xue Cun
The E-J relationship in conventional conductor generally satisfies linear Ohm's law. However, the E-J model in superconductors presents strong nonlinear characteristics, which is significantly different from that of conventional conductor.With the nonlinear E-J power law of superconducting materials by using the fast Fourier transform method (FFT), we quantitatively investigate the relationship between the magnetic-thermal stability and the nonlinear constitutive relation of superconducting films at different temperature, magnetic field ramp rate and critical current density. We find that the strong nonlinear electromagnetic constitutive model plays a crucial role in the onset and morphology (tree-like and finger-like) of the magnetothermal instability of superconducting thin films. In addtion, the reason why similar magneto-thermal instabilities cannot be observed in conventional conductors is also explained. It can be found that the magnetic field on the border of the superconducting film increases rapidly for a larger creep exponent due to the enhancement of diamagnetism, which results in a large magnetic pressure and easily trigger flux avalanches. Therefore, the threshold field of flux avalanches in superconducting film decreases with flux creep exponent. Finally, we present the curves that can clearly divide the n0 - jc0 plane and n0-Ḣa plane into magneto-thermal stability region and magnetothermal stability regions for superconducting thin film with different levels of nonlinearity.
