The behaviour of the magnetic flux in a double-junction SQUID influenced by a jump-like alteration of the external magnetic field

1981 ◽  
Vol 68 (2) ◽  
pp. 489-498 ◽  
Author(s):  
W. D. Schmidt ◽  
W. Krech
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Double Junction

scholarly journals Collimation of hot electron beams by external field from magnetic-flux compression

2013 ◽  
Vol 31 (4) ◽  
pp. 579-582 ◽  
Author(s):  
Yuqiu Gu ◽  
Jinqing Yu ◽  
Weimin Zhou ◽  
Fengjuan Wu ◽  
Jian Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
External Field ◽  
Fast Ignition ◽  
Hot Electrons ◽  
Hot Electron ◽  
Flux Compression ◽  
Magnetic Flux Compression

AbstractIn fast ignition of inertial confinement fusion, hot electron beam is considered to be an appropriate energy source for ignition. However, hot electrons are divergent as they are transporting in over-dense plasma. So collimating the hot electrons becomes one of the most important issues in fast ignition. A method to collimate hot electron beam by external magnetic field is proposed in this paper. The external field can be generated by compressing a seed magnetic field at the stage of laser-driven implosion. This method is confirmed by particle-in-cell simulations. The results show that hot electrons are well collimated by external magnetic field from magnetic-flux compression.

scholarly journals Distribution of magnetic field around simply and multiply connected supraconductors

1936 ◽  
Vol 157 (890) ◽  
pp. 132-146 ◽  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Meissner Effect ◽  
The Body ◽  
Persistent Current ◽  
Closed Circuit ◽  
Multiply Connected ◽  
Constant Flux ◽  
Connected Body

The experiments to be described in this paper arose from a suggestion by M. von Laue that it would be of interest to examine more closely the behaviour of simply and multiply connected supraconducting bodies in an external magnetic field. If a closed circuit be taken wholly within a supraconducting body, sufficiently far from the surface, the magnetic flux through the circuit should be constant as long as no part of the body is subjected to a magnetic field greater than the critical field strength. For a simply connected body, if the spontaneous ejection of flux on cooling through the transition point, the so-called Meissner effect, is complete, the constant flux through any circuit should be zero. For a multiply connected body, it should be equal to the value immediately after the body became supraconducting. Only in the case of a multiply connected body, that is, a closed circuit, can there be a resultant current through any cross-section in the steady state. This may be taken as a definition of the current I in the circuit, the so-called persistent current. Let L be the self-inductance of the circuit, calculated for the supraconducting state on the assumption that the current flows entirely in a layer very close to the surface. Let ϕ be the calculated magnetic flux through the circuit due to external magnetic field, allowing for the distortion of the field by the presence of supraconducting material. Then, if it can be assumed that the maintenance of the constant flux through the closed circuit is due to a persistent current in the above sense, the law of constant flux can be written in the form LI + ϕ = ϕ 0 . (1)

The Thermoelectric-Hydromagnetic Pump

1964 ◽  
Vol 86 (2) ◽  
pp. 166-168 ◽  
Author(s):  
J. F. Osterle ◽  
S. W. Angrist
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Pressure Rise ◽  
Maximum Efficiency ◽  
Magnetic Flux Density ◽  
Optimum Thickness ◽  
Pumping Power ◽  
Electrically Conducting

A thermally powered pump for fluids which are electrically conducting, which utilizes the Lorentz force between an electric current induced by the Seebeck effect, and an external magnetic field is examined. The pressure rise in the pump is found to be proportional to the magnetic flux density while the flow rate is found to be inversely proportional to the magnetic flux density. Thus the pumping power and efficiency (both being proportional to the product of pressure rise and flow) are independent of the applied magnetic field. Calculations for a pump with constantan walls handling sodium and utilizing a temperature difference of 300 deg C show that a maximum efficiency of close to seven-tenths of a percent is possible. If the same pump is constructed with optimum thickness walls made of the semiconductor AgSbTe2, it would have an efficiency of nearly six percent.

scholarly journals PERSISTENT SPIN CURRENT AND ENTANGLEMENT IN THE ANISOTROPIC SPIN RING

2007 ◽  
Vol 21 (06) ◽  
pp. 327-337 ◽  
Author(s):  
ZI-XIANG HU ◽  
YOU-QUAN LI
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Ground State ◽  
State Energy ◽  
Spin Current ◽  
Persistent Current ◽  
One Dimensional ◽  
The Magnetic Field ◽  
Twisted Boundary Conditions

We investigate the ground state persistent spin current and the pair entanglement in one-dimensional antiferromagnetic anisotropic Heisenberg ring with twisted boundary conditions. By solving Bethe ansatz equations numerically, we calculate the dependence of the ground state energy on the total magnetic flux through the ring, and the resulting persistent current. Motivated by the recent development of the quantum entanglement theory, we study the properties of the ground state concurrence under the influence of the flux through the anisotropic Heisenberg ring. We also include an external magnetic field and discuss the properties of the persistent current and the concurrence in the presence of the magnetic field.

SURFACE BARRIER IN THE MIXED STATE OF ANISOTROPIC SUPERCONDUCTOR

1993 ◽  
Vol 07 (12) ◽  
pp. 841-847
Author(s):  
T. KRZYSZTON
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Flux Density ◽  
Surface Barrier ◽  
Anisotropy Axis ◽  
Anisotropic Superconductor ◽  
Applied External Magnetic Field ◽  
London Theory

In the framework of London theory, the problem of equilibrium between magnetic flux density in the anisotropic superconductor and the applied external magnetic field is studied. The Gibbs free energy of a fluxoid in the presence of magnetic flux density in the sample is calculated. As a result, critical entry and exit fields are calculated and their dependence upon the angle which makes anisotropy axis and the direction of an external magnetic field.

scholarly journals Dynamics of magnetic flux tubes in accretion discs of T Tauri stars

2019 ◽  
Vol 487 (4) ◽  
pp. 5388-5404 ◽  
Author(s):  
A E Dudorov ◽  
S A Khaibrakhmanov ◽  
A M Sobolev
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
T Tauri Stars ◽  
Accretion Discs ◽  
Magnetic Field Generation ◽  
Flux Tubes ◽  
T Tauri ◽  
Magnetic Flux Tubes ◽  
Magnetic Oscillations

Abstract Dynamics of slender magnetic flux tubes (MFTs) in the accretion discs of T Tauri stars is investigated. We perform simulations taking into account buoyant, aerodynamic, and turbulent drag forces, radiative heat exchange between MFT and ambient gas, and magnetic field of the disc. The equations of MFT dynamics are solved using Runge–Kutta method of the fourth order. The simulations show that there are two regimes of MFT motion in absence of external magnetic field. In the region r < 0.2 au, the MFTs of radii $0.05 \le a_0 \le 0.16\, H$ (H is the scale height of the disc) with initial plasma beta of 1 experience thermal oscillations above the disc. The oscillations decay over some time, and MFTs continue upward motion afterwards. Thinner or thicker MFTs do not oscillate. MFT velocity increases with initial radius and magnetic field strength. MFTs rise periodically with velocities up to 5–15 km s−1 and periods of 0.5–10 yr determined by the toroidal magnetic field generation time. Approximately 20 per cent of disc mass and magnetic flux can escape to disc atmosphere via the magnetic buoyancy over characteristic time of disc evolution. MFTs dispersal forms expanding magnetized corona of the disc. External magnetic field causes MFT oscillations near the disc surface. These magnetic oscillations have periods from several days to 1–3 months at r < 0.6 au. The magnetic oscillations decay over few periods. We simulate MFT dynamics in accretion discs in the Chameleon I cluster. The simulations demonstrate that MFT oscillations can produce observed IR-variability of T Tauri stars.

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