magnetic field Quick reference
A Dictionary of Construction, Surveying and Civil Engineering (2 ed.)
... field A force field surrounding a magnetized object (a magnet) or an area (the Magnetic North or South...
magnetic field Reference library
Oxford Dictionary of Biochemistry and Molecular Biology (2 ed.)
... field 1 a field of force existing in the neighbourhood of either a permanent magnet or a circuit carrying an electric current. Another magnet will experience a couple when placed in a magnetic field. 2 an alternative name for magnetic field strength...
magnetic field Quick reference
A Dictionary of Environment and Conservation (3 ed.)
... field A field of force that is generated by electric currents. The Earth's magnetic field is believed to be generated by the rotation of the molten iron–nickel outer core around the solid inner core , like a dynamo. See also palaeomagnetism...
magnetic field Quick reference
The Concise Oxford Dictionary of Mathematics (6 ed.)
...magnetic field A vector field which exerts a force on moving electric charges. See Maxwell’s equations...
magnetic field Quick reference
A Dictionary of Physics (8 ed.)
...magnetic field A field of force that exists around a magnetic body ( see magnetism ) or a current-carrying conductor. Within a magnetic field a magnetic dipole may experience a torque and a moving charge may experience a force. The strength and direction of the field can be given in terms of the magnetic flux density (or magnetic induction ), symbol B ; it can also be given in terms of the magnetic field strength ( magnetizing force or magnetic intensity ), symbol H . The magnetic flux density is a vector quantity and is the magnetic flux ...
magnetic field Quick reference
A Dictionary of Space Exploration (3 ed.)
...magnetic field The region around a permanent magnet, or around a conductor carrying an electric current, in which a force acts on a moving charge or on a magnet placed in the field. The force cannot be seen; only the effects it produces are visible. The field can be represented by lines of force parallel at each point to the direction of a small compass needle placed on them at that point. These invisible lines of force are called the magnetic field or the flux lines. A magnetic field's magnitude is given by the magnetic flux density (the number of flux lines...
magnetic field Quick reference
A Dictionary of Electronics and Electrical Engineering (5 ed.)
... field The space surrounding a magnet or a current-carrying conductor and containing magnetic flux . It may be represented by lines of force whose direction at any point is the direction of the force exerted on a small coil (a search coil) placed in the field at that point. The direction of the force is normal to the magnetic flux density at that point. It is assumed that the dimensions of the coil are sufficiently small so as not to disturb the magnetic conditions. ...
magnetic field Quick reference
World Encyclopedia
... field Region surrounding a magnet , or a conductor through which a current is flowing, in which magnetic effects, such as the deflection of a compass needle, can be detected. A magnetic field can be represented by a set of lines of force (flux lines) spreading out from the poles of a magnet or running around a current-carrying conductor. The direction of a magnetic field is the direction a tiny magnet takes when placed in the field. Magnetic poles are the field regions in which magnetism appears to be concentrated. If a bar magnet is suspended to...
pseudo-magnetic field Quick reference
A Dictionary of Geology and Earth Sciences (5 ed.)
...magnetic field A magnetic field that is transformed to simulate gravitational acceleration for the purpose of computational...
intergalactic magnetic field Quick reference
A Dictionary of Astronomy (3 ed.)
...magnetic field The weak magnetic field of less than 10 −12 tesla believed to be present in the space between galaxies. The intergalactic field may have arisen spontaneously in the very early Universe, or from the effect of atomic particles and magnetic fields from cosmic radio sources. It could be ten times stronger in clusters of...
magnetic field strength Reference library
Oxford Dictionary of Biochemistry and Molecular Biology (2 ed.)
... field strength or magnetic field or (formerly) magnetic intensity symbol : H (italic bold); a vector quantity, the magnetizing force at any point in a medium. It is measured by a couple that would act on a small magnet of unit moment placed at that point with its axis at right angles to the direction of the magnetic field. It is the magnetic flux density , B , divided by the permeability , μ ; i.e. H = B / μ . The SI derived unit H = A m −1...
galactic magnetic field Quick reference
A Dictionary of Astronomy (3 ed.)
...magnetic field The magnetic field in interstellar space in the disk of a galaxy. Magnetic field strengths between 10 −9 and 10 −10 tesla occur in the disks of spiral galaxies, with an overall pattern roughly following the spiral structure. Fields in elliptical galaxies are much more difficult to estimate, but in those that are strong radio emitters it appears that the fields may reach 10 −7 ...
magnetic field strength (symbol: H; unit: ampere/metre) Quick reference
A Dictionary of Electronics and Electrical Engineering (5 ed.)
... field strength ( magnetizing force ) ( symbol: H ; unit: ampere/metre ) The strength of a magnetic field at a point in the direction of the line of force at that point. It is defined in a vacuum from the equation B = μ 0 H where B is the magnetic flux density and μ 0 is a constant, the permeability of free space. See also Ampere’s law . ...
alternating-magnetic-field demagnetization Quick reference
A Dictionary of Geology and Earth Sciences (5 ed.)
...magnetic-field demagnetization ( AF demagnetization , thermal cleaning ) A common method for demagnetizing ( see demagnetization ) rock samples that is widely used in palaeomagnetism and archaeomagnetism because of its simplicity and because it produces no chemical change in the samples. It can cause problems associated with anhysteretic and rotational remanences, and is only fully suitable for magnetite -bearing rock...
magnetic field (origin of the Earth's internal field) Reference library
The Oxford Companion to the Earth
...dynamo model. The single-disc dynamo of Larmor (a) is able to reinforce an initial magnetic field, but a coupled double-disc dynamo (b) is also able to replicate the chaotic reversals observed in nature. H magnetic field. Geomagnetists deciphering the mysteries of the origin of the Earth's magnetic field constrain their models with snapshots of the magnetic field obtained from a variety of sources: satellites such as Magsat ( c. 1980 ), which measure the near-Earth magnetic field; the POGO series satellites flown in the mid-1960s; surface geomagnetic...
magnetic field strength Reference library
The New Oxford Dictionary for Scientific Writers and Editors (2 ed.)
... field strength Symbol: H A *vector quantity, the ratio of *magnetic flux density B to the *permeability , μ, of the medium. The direction at a given point is that of the flux density at that point. The *SI unit is the ampere per metre. Also called magnetic field...
