scholarly journals Formation of dense plasma on the surface of a stainless steel conductor in superstrong magnetic fields

2021 ◽  
Vol 2064 (1) ◽  
pp. 012034
Author(s):  
V A Kokshenev ◽  
R K Cherdizov ◽  
N E Kurmaev
Keyword(s):  
Magnetic Field ◽  
Stainless Steel ◽  
Magnetic Fields ◽  
Dense Plasma ◽  
Critical Magnetic Field ◽  
Explosion Products ◽  
Interelectrode Gap ◽  
Layer Sample ◽  
Aisi 321 ◽  
The Moment

Abstract In experiments on the GIT-12 megaampere generator, the characteristics of conductors made of AISI 321 stainless steel were investigated in the microsecond regime of increasing superstrong magnetic fields. In this regime, a skin explosion of the conductor material takes place with the formation of a dense plasma and its expansion into the interelectrode gap of the vacuum transmission line. The values of the characteristic magnetic field B0 = 100 T are determined, above which there is the effect of nonlinear diffusion of the magnetic field into the conductor, and the critical magnetic field BCT ≅ 260 T, the excess of which leads to the formation of dense plasma on the surface of the massive conductor. A method is proposed for increasing the critical magnetic field on the surface of a conductor up to 1.5 times by choosing the optimal thickness of the conducting surface, and criteria for its determination are given. The effect of increasing the critical magnetic field on the surface of a two-layer sample and creating a pressure in the Mbar range until the moment of formation and expansion of explosion products of an inner conductor with high conductivity has been tested.

scholarly journals Restoration of superconductivity in high magnetic fields in UTe2

2020 ◽  
Vol 34 (32) ◽  
pp. 2030007
Author(s):  
Andrei G. Lebed
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Superconducting State ◽  
Critical Magnetic Field ◽  
High Magnetic Fields ◽  
Two Dimensional ◽  
Upper Critical Magnetic Field ◽  
Reentrant Superconductivity ◽  
Theoretical Results ◽  
General Method

It was theoretically predicted more than 20 years ago [A. G. Lebed and K. Yamaji, Phys. Rev. Lett. 80, 2697 (1998)], that a triplet quasi-two-dimensional (Q2D) superconductor could restore its superconducting state in parallel magnetic fields, which are higher than its upper critical magnetic field, [Formula: see text]. It is very likely that, recently, such phenomenon has been experimentally discovered in the Q2D superconductor UTe2 by Nicholas Butch, Sheng Ran, and their colleagues and has been confirmed by Japanese–French team. We review our previous theoretical results using such a general method that it describes the reentrant superconductivity in the abovementioned compound and will hopefully describes the similar phenomena, which can be discovered in other Q2D superconductors.

scholarly journals Effect of Low Magnetic Field on Biomimetic Deposition of Hydroxyapatite on Titanium and BIOLINE Stainless Steel

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1484
Author(s):  
Rafael Uribe ◽  
Andrea Uvillús ◽  
Omar Bonilla ◽  
Luis Lascano ◽  
Gema González
Keyword(s):  
Magnetic Field ◽  
Contact Angle ◽  
Stainless Steel ◽  
Magnetic Fields ◽  
Body Fluid ◽  
Metallic Substrates ◽  
Physiological Conditions ◽  
Low Magnetic Field ◽  
Biomimetic Deposition

In this work, we evaluated the effect of a low magnetic field on the deposition of hydroxyapatite (HAp) on different metallic substrates. The substrates studied were titanium and BIOLINE stainless steel SS316LVM with and without Ta and TaN/Ta coatings. Before deposition, the uncoated Ti and SS316LVM substrates were treated with alkali to improve the adhesion of the films prompted to be formed. Next, all substrates (coated and uncoated) were immersed in stimulated body fluid (SBF) at physiological conditions of 37 °C, pH = 7.4, in the presence of magnetic fields from 0.15 T and 0.22 T for 7, 10, and 14 days. The formed films were characterized using SEM, FTIR, and the contact angle. Ti and SS316LVM substrates presented Ca/P relations closer to the stoichiometric HAp. It was demonstrated that in both coatings, Ta and Ta/N, an increase of the bioactivity was obtained. Additionally, our results showed that the application of magnetic fields has a significant effect on the increment in the mass:area ratio of HAp. Finally, the contact angle values were lower than 90°, showing an increase in hydrophilicity with respect to the metallic substrates.

Characterization of Superconducting PrBa2Cu3Ox

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3242-3250
Author(s):  
Zhigang Zou ◽  
Jinhua Ye ◽  
Kunihiko Oka ◽  
Yoshikazu Nishihara
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Single Crystals ◽  
Superconducting State ◽  
Magnetic Measurement ◽  
Stacking Faults ◽  
Critical Magnetic Field ◽  
Oxygen Annealing ◽  
X Ray

The crystal structures of superconducting and nonsuperconducting PrBa2Cu3O x crystals were investigated using a single crystal X-ray precession camera. A large amount of stacking faults were observed in h0l reflections of as-grown supconducting PrBa2Cu3O x single crystals. These diffusing could be relaxed after oxygen annealing. Meanwhile, intensities of 003n (n = 1, 2, 3…) diffraction reflections of annealed crystal were increased significantly, indicating that the structural ordering of 1/3n unit cell was improved. Magnetic measurement exhibited that the superconducting state of PrBa2Cu3O x , is sensitive to magnetic fields and the magnetic fields dependence of the flux melting temperature showed that the sample has the smaller critical magnetic field than YBa2Cu3O x.

scholarly journals Magnetic Field Diagnosis Through Spectropolarimetry)

1993 ◽  
Vol 138 ◽  
pp. 232-246 ◽  
Author(s):  
Gautier Mathys
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Longitudinal Magnetic Field ◽  
Quadratic Field ◽  
Spectral Lines ◽  
Stellar Rotation ◽  
The Asymmetry ◽  
The Moment ◽  
Ap Stars ◽  
Original Approach

AbstractAn original approach, the moment technique, is applied to analyze the shapes of spectral lines of Ap stars recorded in both circular polarizations. The longitudinal magnetic field, the asymmetry of the longitudinal magnetic field, and the quadratic field of the studied stars are derived. From the consideration of these quantities and of their variations through the stellar rotation cycle, constraints on the spatially unresolved structure of the magnetic fields are obtained.

STUDY OF ACOUSTIC ATTENUATION IN HEAVY FERMION SYSTEMS

2011 ◽  
Vol 25 (15) ◽  
pp. 2081-2090
Author(s):  
KWANG-HUA W. CHU
Keyword(s):  
Magnetic Field ◽  
Kinetic Model ◽  
Magnetic Fields ◽  
Heavy Fermion ◽  
Critical Magnetic Field ◽  
High Magnetic Fields ◽  
Orientation Parameter ◽  
Acoustic Attenuation ◽  
Fermion Systems ◽  
Heavy Fermion Systems

Quantum kinetic model together with the introduction of a field-tuned orientation parameter are adopted to study the acoustic attenuations of heavy fermion systems in high magnetic fields. The calculated attenuation-peak results near the critical (magnetic) field (Bc) obtained here resemble qualitatively those measured before in heavy fermion systems.

An Energy Method for Analyzing Magnetoelastic Buckling and Bending of Ferromagnetic Plates in Static Magnetic Fields

1999 ◽  
Vol 66 (4) ◽  
pp. 913-917 ◽  
Author(s):  
W. Yang ◽  
H. Pan ◽  
D. Zheng ◽  
Q. Cai
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Energy Method ◽  
Transverse Field ◽  
Critical Magnetic Field ◽  
Thin Plates ◽  
Static Magnetic Fields ◽  
Theoretical Predictions ◽  
Main Factors ◽  
Longitudinal Fields

Based on an energy method analyses of magnetoelastic buckling and bending of ferromagnetic thin plates in transverse, oblique, and longitudinal fields are performed in this paper. A general expression of the critical magnetic field of the plate in a transverse field is presented. It is shown that the critical magnetic field is not only related to the ratio of the thickness to the cantilevered length, but also to the susceptibility and the demagnetizing factors that are primarily dependent on the ratios of the thickness to width and the thickness to the total length. In different cases, main factors that affect the critical magnetic field are discussed. Theoretical predictions agree with experimental results reasonably.

Calculated Coronal Magnetic Fields and Their Comparison with the Coronal Structures as Observed during Five Solar Eclipses

1994 ◽  
Vol 144 ◽  
pp. 559-564
Author(s):  
P. Ambrož ◽  
J. Sýkora
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Coronal Magnetic Field ◽  
Coronal Magnetic Fields ◽  
Solar Eclipses ◽  
Coronal Structures

AbstractWe were successful in observing the solar corona during five solar eclipses (1973-1991). For the eclipse days the coronal magnetic field was calculated by extrapolation from the photosphere. Comparison of the observed and calculated coronal structures is carried out and some peculiarities of this comparison, related to the different phases of the solar cycle, are presented.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

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