scholarly journals Casimir Effect between Superconducting Plates in the Mixed State

2021 ◽  
Vol 3 (4) ◽  
pp. 731-745
Author(s):  
Norio Inui
Keyword(s):  
Magnetic Field ◽  
Mixed State ◽  
Imaginary Axis ◽  
Casimir Force ◽  
Casimir Effect ◽  
Normal Phase ◽  
Superconducting Phase ◽  
Type Ii ◽  
Plasma Model ◽  
The Magnetic Field

The Casimir effect between type-II superconducting plates in the coexisting phase of a superconducting phase and a normal phase is investigated. The dependence of the optical conductivity of the superconducting plates on the external magnetic field is described in terms of the penetration depth of the incident electromagnetic field, and the permittivity along the imaginary axis is represented by a linear combination of the permittivities for the plasma model and Drude models. The characteristic frequency in each model is determined using the force parameters for the motion of the magnetic field vortices. The Casimir force between parallel YBCO plates in the mixed state is calculated, and the dependence on the applied magnetic field and temperature is considered.

Magnetic-field dependence of the surface impedance in the mixed state of type-II superconductors

1994 ◽  
Vol 49 (6) ◽  
pp. 4331-4333 ◽  
Author(s):  
V. A. Berezin ◽  
E. V. Il’ichev ◽  
V. A. Tulin ◽  
E. B. Sonin ◽  
A. K. Tagantsev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Dependence ◽  
Mixed State ◽  
Surface Impedance ◽  
Magnetic Field Dependence ◽  
Type Ii ◽  
Type Ii Superconductors

STUDY OF PHASE PROPAGATION IN SUPERCONDUCTING ALUMINUM BY ULTRASONIC ATTENUATION MEASUREMENTS

1959 ◽  
Vol 37 (5) ◽  
pp. 614-618 ◽  
Author(s):  
K. L. Chopra ◽  
T. S. Hutchison
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Ultrasonic Attenuation ◽  
Cylindrical Specimen ◽  
Current Theory ◽  
Superconducting Phase ◽  
Rate Of Change ◽  
Time Rate ◽  
Phase Propagation ◽  
The Magnetic Field

The phase propagation in superconducting aluminum has been studied by measuring the time rate of change of ultrasonic attenuation. The time taken for the destruction of the superconducting phase in a cylindrical specimen, by means of a magnetic field, H, greater than the critical field, Hc, is approximately proportional to{H/(H–Hc)} in agreement with eddy-current theory. In the converse case, where the superconducting phase is restored by switching off the magnetic field H (>Hc), the total time taken is nearly independent of the temperature (or Hc) as well as H. The superconducting phase grows at a non-uniform volume rate which is considerably less than the uniform rate of collapse.

scholarly journals Analyzing the propagation of EUV waves and their connection with type II radio bursts by combining numerical simulations and multi-instrument observations

2020 ◽  
Vol 644 ◽  
pp. A90
Author(s):  
A. Koukras ◽  
C. Marqué ◽  
C. Downs ◽  
L. Dolla
Keyword(s):  
Magnetic Field ◽  
Wave Front ◽  
Ray Tracing ◽  
Radio Burst ◽  
Radio Bursts ◽  
Type Ii ◽  
Fast Mode ◽  
Type Ii Radio Bursts ◽  
The Magnetic Field ◽  
Burst Emission

Context. EUV (EIT) waves are wavelike disturbances of enhanced extreme ultraviolet (EUV) emission that propagate away from an eruptive active region across the solar disk. Recent years have seen much debate over their nature, with three main interpretations: the fast-mode magneto-hydrodynamic (MHD) wave, the apparent wave (reconfiguration of the magnetic field), and the hybrid wave (combination of the previous two). Aims. By studying the kinematics of EUV waves and their connection with type II radio bursts, we aim to examine the capability of the fast-mode interpretation to explain the observations, and to constrain the source locations of the type II radio burst emission. Methods. We propagate a fast-mode MHD wave numerically using a ray-tracing method and the WKB (Wentzel-Kramers-Brillouin) approximation. The wave is propagated in a static corona output by a global 3D MHD Coronal Model, which provides density, temperature, and Alfvén speed in the undisturbed coronal medium (before the eruption). We then compare the propagation of the computed wave front with the observed wave in EUV images (PROBA2/SWAP, SDO/AIA). Lastly, we use the frequency drift of the type II radio bursts to track the propagating shock wave, compare it with the simulated wave front at the same instant, and identify the wave vectors that best match the plasma density deduced from the radio emission. We apply this methodology for two EUV waves observed during SOL2017-04-03T14:20:00 and SOL2017-09-12T07:25:00. Results. The simulated wave front displays a good qualitative match with the observations for both events. Type II radio burst emission sources are tracked on the wave front all along its propagation. The wave vectors at the ray-path points that are characterized as sources of the type II radio burst emission are quasi-perpendicular to the magnetic field. Conclusions. We show that a simple ray-tracing model of the EUV wave is able to reproduce the observations and to provide insight into the physics of such waves. We provide supporting evidence that they are likely fast-mode MHD waves. We also narrow down the source region of the radio burst emission and show that different parts of the wave front are responsible for the type II radio burst emission at different times of the eruptive event.

scholarly journals Expansion of the high field-boosted superconductivity in UTe2 under pressure

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Sheng Ran ◽  
Shanta R. Saha ◽  
I-Lin Liu ◽  
David Graf ◽  
Johnpierre Paglione ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Field ◽  
Superconducting Phase ◽  
High Symmetry ◽  
First Order ◽  
Superconducting Phases ◽  
Quantum Phenomenon ◽  
Zero Resistance ◽  
Spin Triplet ◽  
The Magnetic Field

AbstractMagnetic field-induced superconductivity is a fascinating quantum phenomenon, whose origin is yet to be fully understood. The recently discovered spin-triplet superconductor, UTe2, exhibits two such superconducting phases, with the second one reentering in the magnetic field of 45 T and persisting up to 65 T. More surprisingly, in order to induce this superconducting phase, the magnetic field has to be applied in a special angle range, not along any high symmetry crystalline direction. Here we investigated the evolution of this high-field-induced superconducting phase under pressure. Two superconducting phases merge together under pressure, and the zero resistance persists up to 45 T, the field limit of the current study. We also reveal that the high-field-induced superconducting phase is completely decoupled from the first-order field-polarized phase transition, different from the previously known example of field-induced superconductivity in URhGe, indicating superconductivity boosted by a different paring mechanism.

The interphase surface energy in some pure and impure superconductors

1960 ◽  
Vol 255 (1282) ◽  
pp. 407-426 ◽  
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Surface Energy ◽  
Detailed Analysis ◽  
Energy Parameter ◽  
Transverse Magnetic ◽  
Superconducting Phase ◽  
Interphase Surface ◽  
Dilute Alloys ◽  
The Magnetic Field

A new method has been developed for obtaining relative values of the surface energy parameter, Δ, in superconductors. It involves the measurement of the resistance of thin films subjected to a transverse magnetic field. The method has been applied to tin, indium and aluminium and to dilute alloys of the first two. The principal new results are that Δ is 1⋅48 times larger in indium than in tin and that the addition of impurity to either metal lowers Δ without changing the nature of its temperature dependence. These conclusions are compared with current theories of the interphase surface energy. An attempt has been made to deduce the absolute magnitude of Δ, which requires a detailed analysis of the way in which the last traces of the superconducting phase are eliminated from the film by the action of the magnetic field. The analysis is necessarily over-simplified but it does give a figure for Δ in pure tin which is reasonably consistent with the previous estimates of Faber and Sharvin.

scholarly journals Coherence length of magnetic field in the mixed state of type-II superconductors

2011 ◽  
Vol 303 ◽  
pp. 012114
Author(s):  
P Belova ◽  
M Safonchik ◽  
K B Traito ◽  
E Lähderanta
Keyword(s):  
Magnetic Field ◽  
Mixed State ◽  
Coherence Length ◽  
Type Ii ◽  
Type Ii Superconductors

Shock Drift Acceleration and Type II Solar Radio Bursts

1994 ◽  
Vol 11 (1) ◽  
pp. 21-24 ◽  
Author(s):  
Arthur G. Street ◽  
Lewis Ball ◽  
D. B. Melrose
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Shock Front ◽  
Solar Radio ◽  
Radio Bursts ◽  
Type Ii ◽  
Solar Radio Bursts ◽  
Type Ii Bursts ◽  
Herringbone Structure ◽  
The Magnetic Field

AbstractShock drift acceleration of the electrons which produce herringbone structure in type II bursts is considered. A non-coplanar component of the magnetic field within the shock front and an electric field across the shock are taken into account. A quantitative difficulty with shock drift acceleration is identified, and possible ways of overcoming the difficulty are outlined.

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