London moment

London field
The London moment (after Fritz London) is a quantum-mechanical phenomenon whereby a spinning superconductor generates a magnetic field whose axis lines up exactly with the spin axis.wikipedia
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Superconductivity

superconductingsuperconductorsuperconductors
The London moment (after Fritz London) is a quantum-mechanical phenomenon whereby a spinning superconductor generates a magnetic field whose axis lines up exactly with the spin axis. The term may also refer to the magnetic moment of any rotation of any superconductor, caused by the electrons lagging behind the rotation of the object, although the field strength is independent of the charge carrier density in the superconductor. The GP-B gyro consists of a nearly-perfect spherical rotating mass made of fused quartz, which provides a dielectric support for a thin layer of niobium superconducting material.
The effect, the London moment, was put to good use in Gravity Probe B.

Fritz London

FritzLondonLondon, Fritz Wolfgang
The London moment (after Fritz London) is a quantum-mechanical phenomenon whereby a spinning superconductor generates a magnetic field whose axis lines up exactly with the spin axis.
London also developed a theory of a rotational response of a superconductor, pointing out that rotation of a superconductor generates magnetic field London moment.

Gravity Probe B

For example, those used in the Gravity Probe B experiment measured changes in gyroscope spin axis orientation to better than 0.5 milliarcseconds (1.4 degrees) over a one-year period. The GP-B gyro consists of a nearly-perfect spherical rotating mass made of fused quartz, which provides a dielectric support for a thin layer of niobium superconducting material.
(A spinning superconductor generates a magnetic field precisely aligned with the rotation axis; see London moment.)

Quantum mechanics

quantum physicsquantum mechanicalquantum theory
The London moment (after Fritz London) is a quantum-mechanical phenomenon whereby a spinning superconductor generates a magnetic field whose axis lines up exactly with the spin axis.

Phenomenon

phenomenaphenomenalphysical phenomena
The London moment (after Fritz London) is a quantum-mechanical phenomenon whereby a spinning superconductor generates a magnetic field whose axis lines up exactly with the spin axis.

Rotation

rotatingrotatespin
The London moment (after Fritz London) is a quantum-mechanical phenomenon whereby a spinning superconductor generates a magnetic field whose axis lines up exactly with the spin axis. The term may also refer to the magnetic moment of any rotation of any superconductor, caused by the electrons lagging behind the rotation of the object, although the field strength is independent of the charge carrier density in the superconductor.

Magnetic moment

magnetic dipole momentmagnetic momentsdipole moment
The term may also refer to the magnetic moment of any rotation of any superconductor, caused by the electrons lagging behind the rotation of the object, although the field strength is independent of the charge carrier density in the superconductor.

Electron

electronse − electron mass
The term may also refer to the magnetic moment of any rotation of any superconductor, caused by the electrons lagging behind the rotation of the object, although the field strength is independent of the charge carrier density in the superconductor.

Charge carrier density

carrier concentrationcarrier densitycharge carrier densities
The term may also refer to the magnetic moment of any rotation of any superconductor, caused by the electrons lagging behind the rotation of the object, although the field strength is independent of the charge carrier density in the superconductor.

Magnetometer

digital compassDigitalmagnetometry
A magnetometer determines the orientation of the generated field, which is interpolated to determine the axis of rotation.

Interpolation

interpolatedinterpolatinginterpolate
A magnetometer determines the orientation of the generated field, which is interpolated to determine the axis of rotation.

Minute and second of arc

masarcsecondarc second
For example, those used in the Gravity Probe B experiment measured changes in gyroscope spin axis orientation to better than 0.5 milliarcseconds (1.4 degrees) over a one-year period.

Angular distance

angular separationapparent distanceangular separations
This is equivalent to an angular separation the width of a human hair viewed from 32 kilometers (20 miles) away.

Moment of inertia

rotational inertiamoments of inertiamoment of inertia tensor
The GP-B gyro consists of a nearly-perfect spherical rotating mass made of fused quartz, which provides a dielectric support for a thin layer of niobium superconducting material.

Fused quartz

fused silicasilica glassquartz glass
The GP-B gyro consists of a nearly-perfect spherical rotating mass made of fused quartz, which provides a dielectric support for a thin layer of niobium superconducting material.

Dielectric

dielectricsdielectric relaxationpolarization
The GP-B gyro consists of a nearly-perfect spherical rotating mass made of fused quartz, which provides a dielectric support for a thin layer of niobium superconducting material.

Niobium

NbcolumbiumNiobium (Nb)
The GP-B gyro consists of a nearly-perfect spherical rotating mass made of fused quartz, which provides a dielectric support for a thin layer of niobium superconducting material.

Angular acceleration

rotational accelerationradian per second squared1901
After the initial spin-up by a jet of helium which brings the rotor to 4,000 RPM, the polished gyroscope housing is evacuated to an ultra-high vacuum to further reduce drag on the rotor.

Revolutions per minute

rpmr.p.m.RPMs
After the initial spin-up by a jet of helium which brings the rotor to 4,000 RPM, the polished gyroscope housing is evacuated to an ultra-high vacuum to further reduce drag on the rotor.

Rotational symmetry

axis of symmetryaxisymmetricaxis
The London moment (after Fritz London) is a quantum-mechanical phenomenon whereby a spinning superconductor generates a magnetic field whose axis lines up exactly with the spin axis.

SQUID

superconducting quantum interference devicesuperconducting quantum interference devicesDC SQUID
A sensitive DC SQUID magnetometer able to discriminate changes as small as one quantum, or about 2 Wb, is used to monitor the gyroscope.

Magnetic flux quantum

Josephson constantFlux quantizationmagnetic flux quanta
A sensitive DC SQUID magnetometer able to discriminate changes as small as one quantum, or about 2 Wb, is used to monitor the gyroscope.

Weber (unit)

weberWbwebers
A sensitive DC SQUID magnetometer able to discriminate changes as small as one quantum, or about 2 Wb, is used to monitor the gyroscope.

Induction loop

inductive looploop detectorloop detectors
The moving field passes through a superconducting pickup loop fixed to the housing, inducing a small electric current.