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unusual facts about Magnetic field



Astronomy: Observations and Theories

# The Sun: Our Star - Discusses the sun’s interior layers, atmosphere, magnetic cycle, and its effects on Earth.

Background radiation

Astronauts in low orbits, such as in the International Space Station or the Space Shuttle, are partially shielded by the magnetic field of the Earth, but also suffer from the Van Allen radiation belt which accumulates cosmic rays and results from the earths magnetic field.

Bernard Brunhes

In 1905, he found that rocks in an ancient lava flow at Pontfarin in the commune of Cézens (part of the Cantal département) were magnetised in a direction almost opposite to that of the present-day magnetic field.

Fleming's left-hand rule for motors

When electrons, or any charged particles, flow in the same direction (for example, as an electric current in an electrical conductor, such as a metal wire) they generate a cylindrical magnetic field that wraps round the conductor (as discovered by Hans Christian Ørsted).

Gas torus

In the Solar System, gas tori usually are produced by the interaction of a satellite's atmosphere with the magnetic field of a planet, most famously the Io plasma torus, which is produced by the ionization of roughly 1 ton per second of oxygen and sulfur from the tenuous atmosphere of Jupiter's volcanic moon, Io.

Gauss-Matuyama reversal

The Gauss-Matuyama Reversal was a geologic event approximately 2.588 million years ago when the Earth's magnetic field underwent reversal.

Magnetomyography

Magnetomyography (MMG) is a technique for mapping muscle activity by recording magnetic fields produced by electrical currents occurring naturally in the muscles, using arrays of SQUIDs (superconducting quantum interference devices).

Particle-in-cell

The set of equations associated with PIC codes are therefore the Lorentz force as the equation of motion, solved in the so-called pusher or particle mover of the code, and Maxwell's equations determining the electric and magnetic fields, calculated in the (field) solver.

UP Circuit

It also contains the acronyms of the three courses that comprise the EEE program on the magnetic field lines in a representation of a three-phase motor.

Verlet integration

It was also used by Cowell and Crommelin in 1909 to compute the orbit of Halley's Comet, and by Carl Størmer in 1907 to study the motion of electrical particles in a magnetic field.

Wolfson Centre for Magnetics

The power loss, permeability, apparent power, flux density, magnetic field, Barkhausen noise, magnetostriction characteristics of soft magnetic materials and hard magnetic materials can be measured with a range of test systems under DC, AC and rotational magnetising conditions.


see also

Adiabatic theorem

Assuming the magnetic-field dependence is linear, the Hamiltonian matrix for the system with the field applied can be written

Anders Celsius

His research also involved the study of auroral phenomena, which he conducted with his assistant Olof Hiorter, and he was the first to suggest a connection between the aurora borealis and changes in the magnetic field of the Earth.

Andrew D. Huxley

This emergence of an unconventional superconducting state by the application of an external tuning parameter such as magnetic field or pressure is hypothesised to be closely related to a 'Quantum critical point' (QCP) - a special phase transition that occurs at temperatures approaching zero kelvins.

Anjana Ahuja

Ahuja, who was educated at a comprehensive school in Essex, read physics at Imperial College London, followed by a postgraduate course in space physics during which she worked on data about the Sun's magnetic field from the Ulysses probe.

Axion

In the Italian PVLAS experiment polarized light propagates through the magnetic field of a 5 T dipole magnet, searching for a small anomalous rotation of the direction of polarization.

Birkeland current

He rediscovered, using simple magnetic field measurement instruments, that when the aurora appeared the needles of magnetometers changed direction, confirming the findings of Anders Celsius and assistant Olof Hjorter more than a century before.

Composite fermion

More accurately, the vortices bound to electrons produce their own geometric phases which partly cancel the Aharonov–Bohm phase due to the external magnetic field to generate a net geometric phase that can be modeled as an Aharonov–Bohm phase in an effective magnetic field B^*.

When electrons are confined to two dimensions, cooled to very low temperatures, and subjected to a strong magnetic field, their kinetic energy is quenched due to Landau level quantization.

Cross product

It is also used to describe the Lorentz force experienced by a moving electrical charge in a magnetic field.

Electrodynamic suspension

The magnetic field in the train is produced by either superconducting magnets (as in SCMaglev) or by an array of permanent magnets (as in Inductrack).

Fleming's left-hand rule for motors

Michael Faraday introduced a visual analogy for this, in the form of imaginary magnetic lines of force: those in the conductor form concentric circles round the conductor; those in the externally applied magnetic field run in parallel lines.

Flight instruments

While reliable in steady level flight it can give confusing indications when turning, climbing, descending, or accelerating due to the inclination of the Earth's magnetic field.

Francesco Zantedeschi

Zantedeschi's experiments and papers on the repulsion of flames by a strong magnetic field (discovered by Padre Bancalari of the Pious Schools in 1847) attracted general attention at the time.

Hanle

Hanle effect, a reduction in the polarisation of light caused by a magnetic field, named after Wilhelm Hanle

History of geomagnetism

At a given location, a full representation of the Earth's magnetic field requires a vector with three coordinates (see figure).

Hughes Medal

A recent recipient was Michele Dougherty, who was awarded the medal "for innovative use of magnetic field data that led to discovery of an atmosphere around one of Saturn's moons and the way it revolutionised our view of the role of planetary moons in the Solar System".

Interplanetary magnetic field

The dynamic pressure of the wind dominates over the magnetic pressure through most of the solar system (or heliosphere), so that the magnetic field is pulled into an Archimedean spiral pattern (the Parker spiral) by the combination of the outward motion and the Sun's rotation.

L-value

The value assigned to an L-shell, a particular set of planetary magnetic field lines

Lambert W function

The Lambert W function has been recently shown to be the optimal solution for the required magnetic field of a Zeeman slower.

Laplace's law

Biot–Savart law, in electromagnetics, it describes the magnetic field set up by a steady current density.

Lepton

It determines the strength of the electric field generated by the particle (see Coulomb's law) and how strongly the particle reacts to an external electric or magnetic field (see Lorentz force).

LNCMI

The development of this laboratory, as well as the collaboration of the SNCI with the Max Planck Institute from 1972 to 2004, resulted in the production of a record-high magnetic field strength of 31.35 Teslas achieved in 1987, in which the Quantum Hall effect was discovered (Physic Nobel Prize of 1985).

Magnetic core

When the core is subjected to a changing magnetic field, as it is in devices that use AC current such as transformers, inductors, and AC motors and alternators, some of the power that would ideally be transferred through the device is lost in the core, dissipated as heat and sometimes noise.

Magnetic fluid

Magnetorheological fluid, a fluid that changes viscosity when subjected to a magnetic field.

Magnetic memory

Remanence, or residual magnetization, the magnetization left behind in a ferromagnet after an external magnetic field is removed

Magnetic trap

Magnetic tweezers, a trap using a magnetic field to trap micrometre-seized ferromagnetic beads

Penning trap, used to trap charged particles or ions in a combination of electrostatic potential and uniform magnetic field

Magnetorotational instability

In addition to hydrodynamical forces such as pressure and gravity, an element of magnetized fluid also feels the Lorentz force \boldsymbol J\times\boldsymbol B\ , where \boldsymbol J is the current density and \boldsymbol B is the magnetic field vector.

This induced electric field can now itself induce further changes in the magnetic field \boldsymbol B according to Faraday's law,

Magnetospheric eternally collapsing object

Astronomer Rudolph Schild claims to have found evidence of such a magnetic field from the black hole candidate in the quasar Q0957+561.

Mario Acuña

Acuña was a principal investigator on magnetometer experiments flown on numerous missions over the years, from the Pioneer 11 Fluxgate Magnetometer Experiment in 1973 to the Mars Global Surveyor Magnetic Field Experiment in 1994, and the MESSENGER magnetometer.

Motion controller

It was followed by other similar devices, including the ASUS Eee Stick, Sony's PlayStation Move (which also uses magnetometers to track the Earth's magnetic field and computer vision via the PlayStation Eye to aid in position tracking), and HP's Swing.

Multifractal system

They include fully developed turbulence, stock market time series, real world scenes, the Sun’s magnetic field time series, heartbeat dynamics, human gait, and natural luminosity time series.

Nanos scientificae

Maghemite nanoclusters (size 70-150 nm) composed of a number of single SuperParamagnetic Iron Oxide Nanoparticles (sSPIONs™) display much larger magnetic moments needed in applications involving manipulation with magnetic field.

Paleomagnetism

Motonori Matuyama showed that the Earth's magnetic field reversed in the mid-Quaternary, a reversal now known as the Brunhes-Matuyama reversal.

Paul Ulrich Villard

One of those was deflected by a magnetic field (as were the familiar "canal rays") and could be identified with Rutherford's beta rays.

Plasma diagnostics

The model for the plasma bulk is based on 2d-fluid model (zero and first order moments of Boltzmann equation) and the full set of the Maxwellian equations leading to the Helmholtz equation for the magnetic field.

Rotating magnetic field

The discovery of the rotating magnetic field is generally attributed to two inventors, the Italian physicist and electrical engineer Galileo Ferraris, and the Austrian/Serbian inventor and electrical engineer Nikola Tesla.

Sensors for Arc Welding

Inductive sensors evaluate the attenuation of a high-frequency electro-magnetic field which has been generated by eddy currents in the work piece.

That Darn Katz!

The space cats' home planet, Thuban 9, began to lose its rotation, and they discovered that only Earth had the correct orientation and magnetic field with which to harness its rotational energy.

Thermomagnetic convection

B. A. Finlayson first explained in 1970 (in his paper "Convective instability of ferromagnetic fluids", Journal of Fluid Mechanics 40:753-767) how an external magnetic field imposed on a ferrofluid with varying magnetic susceptibility, e.g., due to a temperature gradient, results in a nonuniform magnetic body force, which leads to thermomagnetic convection.

TRM

Thermoremanent magnetization, the magnetic field of a rock after it has cooled below the Curie temperature

Uranium rhodium germanium

The Grenoble team in France, headed by Andrew D. Huxley, first cooled down the sample below its critical temperature and raised the magnetic field to 2 T.

Zeeman

Zeeman effect, the splitting of a spectral line into several components in the presence of a static magnetic field