Damping of the oscillations of a permanent magnet levitating between high-<i>T</i>
                  <i>c</i> superconductors

Grosser, R.; Jäger, J. V.; Betz, J.; Schoepe, Wilfried

doi:10.1063/1.114560

Cited by 10 publications

(3 citation statements)

References 6 publications

(4 reference statements)

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“…Flux motion or flux creep in superconductors often leads to the hysteresis loss of the levitation force. Damping of mechanical vibration by a superconductor in a magnetic field has also been discussed [32,33]. Eddy currents that occur in metallic parts produce ac losses in damping external vibration.…”

Section: Introductionmentioning

confidence: 99%

Hysteresis force loss and damping properties in a practical magnet–superconductor maglev test vehicle

Yang

Liu

Zhang

et al. 2007

Supercond. Sci. Technol.

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In order to investigate the feasible application of a permanent magnet–high-temperature superconductor (PM–HTS) interaction maglev system to a maglev train or a space vehicle launcher, we have constructed a demonstration maglev test vehicle. The force dissipation and damping of the maglev vehicle against external disturbances are studied in a wide range of amplitudes and frequencies by using a sine vibration testing set-up. The dynamic levitation force shows a typical hysteresis behavior, and the force loss is regarded as the hysteresis loss, which is believed to be due to flux motions in superconductors. In this study, we find that the hysteresis loss has weak frequency dependence at small amplitudes and that the dependence increases as the amplitude grows. To analyze the damping properties of the maglev vehicle at different field cooling (FC) conditions, we also employ a transient vibration testing technique. The maglev vehicle shows a very weak damping behavior, and the damping is almost unaffected by the trapped flux of the HTSs in different FC conditions, which is believed to be attributed to the strong pinning in melt-textured HTSs.

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Section: Introductionmentioning

confidence: 99%

Hysteresis force loss and damping properties in a practical magnet–superconductor maglev test vehicle

Yang

Liu

Zhang

et al. 2007

Supercond. Sci. Technol.

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“…Several dynamic levitation experiments have been conducted. Grosser et al [13] measured the velocity amplitude and the resonance frequency (∼150 Hz) of a magnetic microsphere oscillating between two parallel superconducting surfaces of YBa 2 Cu 3 O 7−δ . Jäger et al [14] detected vertical oscillation of a small magnetic sphere, levitating inside a superconducting niobium capacitor immersed in superfluid helium and studied ballistic rotons, phonons, and turbulent drag.…”

Section: Introductionmentioning

confidence: 99%

Oscillation and radiation of a superconducting ring in a Helmholtz coil

Lee

Kim

et al. 2005

Supercond. Sci. Technol.

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We discuss oscillation and radiation of a superconducting ring in a nonuniform magnetic field produced by a Helmholtz coil. This is a simple example of the oscillation of a superconductor between two magnets. Two oscillation modes (the parallel mode and the antiparallel mode) exist, depending on the directions in which the currents flow in the two coils of the Helmholtz coil. Calculations show the following facts. (i) A characteristic radius-to-height ratio of the Helmholtz coil where a maximum frequency can be produced exists. (ii) As the temperature increases, both the parallel and the antiparallel mode frequencies are fixed, but the parallel mode frequency starts to decrease and falls to 0 in a temperature region below the critical temperature, indicating an oscillation in the intermediate state. (iii) When the superconducting ring oscillates with trapped flux in it, as the trapped flux increases, the parallel mode frequency decreases, but the antiparallel mode frequency increases. When the frictional force is not present, radiation alone reduces the motion energy. We show that the oscillations in both modes stop as time approaches infinity. Over time, the amplitude decreases in the form of a root inverse for the parallel mode and decreases exponentially for the antiparallel mode. The half-lives of the amplitudes have been calculated as 2.1 × 1023 years for the parallel mode and 6.9 × 1023 years for the antiparallel mode.

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“…(1) A superconducting suspension of the Nb sphere oscillating in the magnetic field has been used by Hebard [42] as an extremely sensitive tool in the experimental attempt to measure the quarks charges. (2) A tiny PM inside a superconducting capacitor has been used by Grosser et al [43,44] to study the vortex dynamics in HTS films. (3) The well known 'vibrating reed' method [45,46] which, strictly speaking, does not belongs to 'levitation' techniques but is based on the same idea of measuring the elasticity and damping in a superconductor-magnet system has yielded a lot of interesting results about pinning and vortex dynamics in superconducting films [47,48].…”

Section: Resonance Oscillation Techniquementioning

confidence: 99%

Magnetic Flux Dynamics in HTS Bulks with Levitation Techniques

et al. 2002

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The discovery of high-temperature superconductors (HTS) has led to understanding that, in order to explain and utilize the phenomenon, completely new physical approaches should be introduced at all scales: microscopic, mesoscopic, macroscopic. Leaving first two scales beyond the scope of the present paper, we focus in the upper limit of the last scale, the study of the magnetic flux dynamics in HTS bulks-the dynamics of the 'compact vortex structures'. A new direction in the experimental superconducting physics, the investigation of HTS bulks with levitation techniques, which has been elaborated during last years to effectively explore the subject, as well as the new fundamental and applied results obtained there from are overviewed here.Відкриття високотемпературних надпровідників (ВТНП) призвело до розуміння то-го, що задля пояснення та використання цього явища на всіх рівнях: мікроскопічно-му, мезоскопічному та макроскопічному, має бути створено принципово нові фізичні підходи. Полишаючи перші два рівні поза увагою даної роботи, ми детально розгля-даємо верхню границю останнього -дослідження динаміки магнітного потоку в масивних ВТНП, динаміки «компактових вихорових структур». Дана робота -це огляд нового напрямку експериментальної фізики надпровідників -дослідження масивних ВТНП левітаційними методами -що його було вироблено останнім часом для вивчення зазначеної проблеми, а також тих нових фундаментальних та практич-них результатів, що було тут отримано.Открытие высокотемпературных сверхпроводников (ВТСП) привело к пониманию того, что для объяснения и использования этого явления необходимо создание принципиально новых физических подходов на всех уровнях: микроскопическом, мезоскопическом, макроскопическом. Оставляя первые два уровня за рамками данной работы, мы сфокусировали внимание на верхнем пределе последнего -исследовании динамики магнитного потока в массивных ВТСП, динамики «ком-пактных вихревых структур». Данная работа -это обзор нового направления экс-периментальной физики сверхпроводников, которое было выработано за послед- Fiz. Met. 2002, т. 3, сс. 357-386 Оттиски доступны непосредственно от издателя Фотокопирование разрешено только в соответствии с лицензией 2002 ИМФ (Институт металлофизики им. Г. В. Курдюмова НАН Украины) Напечатано в Украине. 358A. A. Kordyuk, V. V. Nemoshkalenko , A. I. Plyushchay, and R. V. Viznichenko ние годы, а также тех новых фундаментальных и прикладных результатов, которые были здесь получены.

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Damping of the oscillations of a permanent magnet levitating between high-T c superconductors

Cited by 10 publications

References 6 publications

Hysteresis force loss and damping properties in a practical magnet–superconductor maglev test vehicle

Hysteresis force loss and damping properties in a practical magnet–superconductor maglev test vehicle

Oscillation and radiation of a superconducting ring in a Helmholtz coil

Magnetic Flux Dynamics in HTS Bulks with Levitation Techniques

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