scholarly journals Superconducting Properties of 3D Low-Density TI-Bipolaron Gas in Magnetic Field

2019 ◽  
Vol 4 (2) ◽  
pp. 43 ◽  
Author(s):  
Victor D. Lakhno
Keyword(s):  
Magnetic Field ◽  
High Temperature Superconductors ◽  
Bose Condensate ◽  
Three Dimensional ◽  
Superconducting Properties ◽  
London Penetration Depth ◽  
Translation Invariant ◽  
Thermodynamical Properties ◽  
Critical Magnetic Fields ◽  
Transition Heat

Consideration is given to thermodynamical properties of a three-dimensional Bose-condensate of translation-invariant bipolarons (TI-bipolarons) in magnetic field. The critical temperature of transition, critical magnetic fields, energy, heat capacity and the transition heat of TI-bipolaron gas are calculated. Such values as maximum magnetic field, London penetration depth and their temperature dependencies are calculated. The results obtained are used to explain experiments on high-temperature superconductors.

scholarly journals Superconducting Properties of 3D Low-Density Translation-Invariant Bipolaron Gas

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
V. D. Lakhno
Keyword(s):  
Heat Capacity ◽  
Transition Energy ◽  
High Temperature Superconductors ◽  
Bose Condensate ◽  
Three Dimensional ◽  
Low Density ◽  
Superconducting Properties ◽  
Translation Invariant ◽  
Thermodynamical Properties ◽  
Transition Heat

Consideration is given to thermodynamical properties of a three-dimensional Bose-condensate of translation-invariant bipolarons (TI-bipolarons). The critical temperature of transition, energy, heat capacity, and the transition heat of ideal TI-bipolaron gas are calculated. The results obtained are used to explain experiments on high-temperature superconductors.

scholarly journals Translation-Invariant Bipolarons and Charge Density Waves in High-Temperature Superconductors

2021 ◽  
Vol 9 ◽  
Author(s):  
Victor D. Lakhno
Keyword(s):  
Charge Density ◽  
High Temperature Superconductors ◽  
Bose Condensate ◽  
Density Wave ◽  
Charge Density Waves ◽  
Superconducting Transition ◽  
Density Waves ◽  
Translation Invariant ◽  
Pseudogap Phase ◽  
Pair Density

A correlation is established between the theories of superconductivity based on the concept of charge density waves (CDWs) and the translation invariant (TI) bipolaron theory. It is shown that CDWs are originated from TI-bipolaron states in the pseudogap phase due to the Kohn anomaly and form a pair density wave (PDW) for wave vectors corresponding to nesting. Emerging in the pseudogap phase, CDWs coexist with superconductivity at temperatures below those of superconducting transition, while their wave amplitudes decrease as a Bose condensate is formed from TI bipolarons, vanishing at zero temperature.

scholarly journals Physics design point of high-field stellarator reactors

2022 ◽  
Author(s):  
J Arturo Alonso ◽  
Ivan Calvo ◽  
Daniel Carralero ◽  
Jose Luis Velasco ◽  
José Manuel García Regaña ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
High Field ◽  
High Temperature Superconductors ◽  
Three Dimensional ◽  
Density Variation ◽  
Similar Degree ◽  
Design Point ◽  
Auxiliary Power ◽  
Fast Ion

Abstract The ongoing development of electromagnets based on High Temperature Superconductors has led to the conceptual exploration of high-magnetic-field fusion reactors of the tokamak type, operating at on-axis fields above 10 T. In this work we explore the consequences of the potential future availability of high-field three-dimensional electromagnets on the physics design point of a stellarator reactor. We find that, when an increase in the magnetic field strength $B$ is used to maximally reduce the device linear size $R\sim B^{-4/3}$ (with otherwise fixed magnetic geometry), the physics design point is largely independent of the chosen field strength/device size. A similar degree of optimization is to be imposed on the magnetohydrodynamic, transport and fast ion confinement properties of the magnetic configuration of that family of reactor design points. Additionally, we show that the family shares an invariant operation map of fusion power output as a function of the auxiliary power and relative density variation. The effects of magnetic field over-engineering and the $R(B)$ scaling of design points with constant neutron wall loading are also inspected. In this study we use geometric parameters characteristic of the \emph{helias} reactor, but most results apply to other stellarator configurations.

scholarly journals Pseudogap Isotope Effect as a Probe of Bipolaron Mechanism in High Temperature Superconductors

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4973
Author(s):  
Victor D. Lakhno
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Isotope Effect ◽  
High Temperature Superconductors ◽  
Translation Invariant ◽  
Pseudogap Phase ◽  
The Magnetic Field

A theory of a pseudogap phase of high-temperature superconductors where current carriers are translation invariant bipolarons is developed. A temperature of T* a transition from a pseudogap phase to a normal one is calculated. For the temperature of a transition to the pseudogap phase, the isotope coefficient is found. It is shown that the results obtained, in particular, the possibility of negative values of the isotope coefficient, are consistent with the experiment. New experiments on the influence of the magnetic field on the isotope coefficient are proposed.

Multiple characteristics of three‐dimensional radiative Cross fluid with velocity slip and inclined magnetic field over a stretching sheet

Heat Transfer ◽  
2021 ◽  
Author(s):  
Hafiz Abdul Wahab ◽  
Syed Zahir Hussain Shah ◽  
Assad Ayub ◽  
Zulqurnain Sabir ◽  
Muhammad Bilal ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Stretching Sheet ◽  
Three Dimensional ◽  
Velocity Slip ◽  
Inclined Magnetic Field ◽  
Multiple Characteristics

Magneto convective flow of casson nanofluid due to Stefan blowing in the presence of bio-active mixers

2021 ◽  
pp. 239779142110166
Author(s):  
Venkatesh Puneeth ◽  
Sarpabhushana Manjunatha ◽  
Bijjanal Jayanna Gireesha ◽  
Rama Subba Reddy Gorla
Keyword(s):  
Magnetic Field ◽  
Brownian Motion ◽  
Convective Flow ◽  
Three Dimensional ◽  
Induced Magnetic Field ◽  
Density Profiles ◽  
Casson Nanofluid ◽  
And Brownian Motion ◽  
Similarity Transformations ◽  
The Mathematical Model

The induced magnetic field for three-dimensional bio-convective flow of Casson nanofluid containing gyrotactic microorganisms along a vertical stretching sheet is investigated. The movement of these microorganisms cause bioconvection and they act as bio-active mixers that help in stabilising the nanoparticles in the suspension. The two forces, Thermophoresis and Brownian motion are incorporated in the Mathematical model along with Stefan blowing. The resulting model is transformed to ordinary differential equations using similarity transformations and are solved using [Formula: see text] method. The Velocity, Induced Magnetic field, Temperature, Concentration of Nanoparticles, and Motile density profiles are interpreted graphically. It is observed that the Casson parameter decreases the flow velocity and enhances the temperature, concentration, and motile density profiles and also it is noticed that the blowing enhances the nanofluid profiles whereas, suction diminishes the nanofluid profiles. On the other hand, it is perceived that the rate of heat conduction is enhanced with Thermophoresis and Brownian motion.

scholarly journals The on-axis magnetic well and Mercier's criterion for arbitrary stellarator geometries

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
P. Kim ◽  
R. Jorge ◽  
W. Dorland
Keyword(s):  
Magnetic Field ◽  
Original Work ◽  
Three Dimensional ◽  
Radial Distance ◽  
Analytical Form ◽  
One Dimensional ◽  
Modern Notation ◽  
Magnetic Well ◽  
First Time ◽  
Dimensional Integral

A simplified analytical form of the on-axis magnetic well and Mercier's criterion for interchange instabilities for arbitrary three-dimensional magnetic field geometries is derived. For this purpose, a near-axis expansion based on a direct coordinate approach is used by expressing the toroidal magnetic flux in terms of powers of the radial distance to the magnetic axis. For the first time, the magnetic well and Mercier's criterion are then written as a one-dimensional integral with respect to the axis arclength. When compared with the original work of Mercier, the derivation here is presented using modern notation and in a more streamlined manner that highlights essential steps. Finally, these expressions are verified numerically using several quasisymmetric and non-quasisymmetric stellarator configurations including Wendelstein 7-X.

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