Persistent current - Persistent current

Japanese: 永久電流 - えいきゅうでんりゅう（英語表記）persistent current; permanent current

A steady current that flows through a closed circuit made of a superconductor without an external electromotive force. The lifetime of persistent current is determined by the movement of the magnetic flux quanta that pass through the superconductor in the case of type II superconductors, and by fluctuations in the superconducting state near the superconducting transition temperature, but is nearly infinite. If a current is passed through a superconducting magnet and then the input of the magnet is short-circuited with a superconductor, persistent current flows, resulting in an extremely stable magnetic field. A similar phenomenon has also been observed with superfluid helium II. (→Superconductivity, Superfluidity)

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

超伝導体でつくった閉回路を外部起電力なしに流れる定常電流。永久電流の寿命は，第二種超伝導体の場合は超伝導体を貫いている磁束量子が動くことにより，また超伝導転移温度の近傍では超伝導状態のゆらぎなどにより決るが，ほとんど無限に近い。超伝導磁石に電流を流しておいたのち，磁石の入力を超伝導体で短絡すると，永久電流が流れるので，きわめて安定な磁場が得られる。超流動ヘリウム IIでも，同様な現象が観測されている。 (→超伝導 ,　超流動 )

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