Crucially important for application of type-II superconductor films is the stability of the vortex matter – magnetic flux lines penetrating the material. If some vortices get detached from pinning centres, the energy dissipated by their motion will facilitate further depinning, and may trigger a massive electromagnetic breakdown. Up to now, the time-resolved behaviour of these ultra-fast events was essentially unknown. We report numerical simulation results revealing the detailed dynamics during breakdown as within nanoseconds it develops branching structures in the electromagnetic fields and temperature, with striking resemblance of atmospheric lightning. During a dendritic avalanche the superconductor is locally heated above its critical temperature, while electrical fields rise to several kV/m as the front propagates at instant speeds near up to 100 km/s. The numerical approach provides an efficient framework for understanding the ultra-fast coupled non-local dynamics of electromagnetic fields and dissipation in superconductor films.
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机译:对于II型超导体薄膜的应用,至关重要的是涡流物质的稳定性-磁通线穿透材料。如果某些涡流从固定中心脱离,则其运动散发的能量将有助于进一步固定,并可能引发大规模的电磁击穿。到目前为止,这些超快速事件的时间分辨行为基本上是未知的。我们报告的数值模拟结果揭示了击穿过程中的详细动态,因为它在纳秒内会在电磁场和温度中形成分支结构,与大气中的闪电非常相似。在树突状雪崩期间,超导体被局部加热到其临界温度以上,而电场随着前沿以接近100 km / s的瞬时速度传播而上升至几kV / m。数值方法为理解超导体薄膜中电磁场和耗散的超快速耦合非局部动力学提供了有效的框架。
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