TY - JOUR

T1 - Thermal and electrodynamical formation mechanisms of overloaded AC states and charging rate influence on their stable dynamics

AU - Romanovskii, V.

AU - Watanabe, Kazuo

AU - Awaji, Satoshi

PY - 2013/9/4

Y1 - 2013/9/4

N2 - The macroscopic thermal and electrodynamical phenomena occurring in high-Tc superconductors during overloaded AC states are theoretically investigated to understand the basic physical mechanisms, which are characteristic for the stable formation of the operating modes when the peak current exceeds the critical current of a superconductor during AC modes. It is shown that there exist characteristic time windows defining the existence of stable overloaded AC states. They identify the stability boundary of the overloaded AC states. Therefore, there is the maximum allowable value of a peak current of stable overloaded AC regimes at the given charging rate, cooling conditions and properties of a superconductor and a matrix. The results obtained prove that the limiting peak current is higher than the corresponding quench current defining the stability margin of DC states. It monotonically increases with the charging rate. Besides, in the stable overloaded AC states, the peak values of the electric field and temperature may be also noticeably higher than the corresponding quench values. They depend on the peak current and charging rate at the given cooling conditions. As a result, high-Tc superconducting tapes can stably work under intensive AC modes without instability onset when the peak of applied currents may significantly exceed not only the critical current but also the corresponding values of DC-quench currents.

AB - The macroscopic thermal and electrodynamical phenomena occurring in high-Tc superconductors during overloaded AC states are theoretically investigated to understand the basic physical mechanisms, which are characteristic for the stable formation of the operating modes when the peak current exceeds the critical current of a superconductor during AC modes. It is shown that there exist characteristic time windows defining the existence of stable overloaded AC states. They identify the stability boundary of the overloaded AC states. Therefore, there is the maximum allowable value of a peak current of stable overloaded AC regimes at the given charging rate, cooling conditions and properties of a superconductor and a matrix. The results obtained prove that the limiting peak current is higher than the corresponding quench current defining the stability margin of DC states. It monotonically increases with the charging rate. Besides, in the stable overloaded AC states, the peak values of the electric field and temperature may be also noticeably higher than the corresponding quench values. They depend on the peak current and charging rate at the given cooling conditions. As a result, high-Tc superconducting tapes can stably work under intensive AC modes without instability onset when the peak of applied currents may significantly exceed not only the critical current but also the corresponding values of DC-quench currents.

KW - AC regimes

KW - High-T superconductor

KW - Instability current

KW - Overloaded current

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U2 - 10.1016/j.physc.2013.07.005

DO - 10.1016/j.physc.2013.07.005

M3 - Article

AN - SCOPUS:84883196357

VL - 495

SP - 25

EP - 32

JO - Physica C: Superconductivity and its Applications

JF - Physica C: Superconductivity and its Applications

SN - 0921-4534

ER -