âhanrobâ (#), meqnâtis (#)
An object that produces a magnetic field around itself.
From L. magnetum (nom. magnes) "lodestone," from Gk. ho Magnes lithos "the Magnesian stone," from Magnesia region in Thessaly where magnetized ore was obtained.
Âhanrobâ, literally "iron attracting, iron robbing," from âhan→ iron + robâ agent noun of robudan, robâyidan
"to attract, to grab, rob;" Av. urūpaiieinti "to cause racking
pain(?);" cf. Skt. rop- "to suffer from abdominal pain,"
rurupas "to cause violent pain," ropaná- "causing
racking pain," rópi- "racking pain;" L. rumpere
"to break;" O.E. reofan "to break, tear."
A highly magnetized → neutron star with fields a thousand times stronger than those of → radio pulsars. There are two sub-classes of magnetars, → anomalous X-Ray pulsar (AXP)s and → soft gamma repeater (SGR)s, that were thought for many years to be separate and unrelated objects. In fact SGRs and AXPs are both neutron stars possessing → magnetic fields of unprecedented strength of 1014 - 1016 G, and that show both steady X-ray pulsations as well as soft gamma-ray bursts. Their inferred steady X-ray luminosities are about one hundred times higher than their → spin-down luminosities, requiring a source of power well beyond the magnetic dipole spin-down that powers → rotation-powered pulsar (RPP)s. New high-energy components discovered in the spectra of a number of AXPs and SGRs require non-thermal particle acceleration and look very similar to high-energy spectral components of young rotation-powered pulsars (A. K. Harding, 2013, Front. Phys. 8, 679).
meqnâtisi (#), meqnâti, âhanrobâyik
Of or pertaining to a magnet or magnetism.
Fr.: advection magnétique
The transport of the magnetic field by a fluid. It is given by the term ∇ x (v x B) in the → induction equation.
Fr.: axe magnétique
botri-ye meqnâtisi (#)
Fr.: bouteille magnétique
Fr.: freinage magnétique
The process whereby a star which loses mass slows down under the action of its → magnetic field. The stellar material follows the → magnetic field lines extending well beyond the stellar surface. The material gain → angular momentum and the underlying object is slowed down. Magnetic braking is an efficient mechanism for removing angular momentum from the the rotating object. See also → disk locking.
Fr.: rayonnement de freinage magnétique
Same as → synchrotron radiation.
Fr.: flottabilité magnétique
The phenomenon whereby the presence of a → magnetic field can make a portion of → compressible fluid less dense than its surroundings, so that it floats upward under the influence of gravity. This magnetic buoyancy is thought, in fact, to be the mechanism by which magnetic flux tubes rise through the Sun's → convection zone and break at the surface in the form of → sunspots. The Sun's rotation would have a major effect on the rate at which these magnetic flux tubes rise. The rotation substantially lengthen the time taken for the flux tubes to reach the surface (D. J. Acheson, 1979, Nature 277, 41).
magnetic cataclysmic binary
dorin-e gatluri-ye meqnâtisi
Fr.: binaire cataclysmique magnétique
A cataclysmic binary in which the white dwarf primary has a strong magnetic field that radically affects the accretion flow in the system. → polar
Fr.: nuage magnétique
A transient ejection in the → solar wind having an enhanced field, a large and smooth change in field direction, and a low → proton temperature compared to the ambient proton temperature (L. F. Burlaga, 1995, Interplanetary Magnetohydrodynamics, Oxford Univ. Press, 89-114).
Fr.: compas magnétique
Fr.: connectivité magnétique
Of magnetic field lines, the condition for them to be connected or the process whereby they become connected or connective.
pâyâ-ye meqnâtisi (#)
Fr.: constante magnétique
A physical constant relating mechanical and electromagnetic units of measurement. It has the value of 4π × 10-7 henry per meter. Also called the permeability of free space, or → absolute permeability.
Fr.: convection magnétique
Thermal → convection modified by the presence of magnetic fields.
Fr.: déclinaison magnétique
Fr.: diffusion magnétique
The process whereby the magnetic field tends to diffuse across the plasma and to smooth out any local inhomogeneities under the influence of a finite resistance in the plasma. For a stationary plasma the → induction equation becomes a pure → diffusion equation: ∂B/∂t = Dm∇2B, where Dm = (μ0σ0)-1 is the → magnetic diffusivity.
Fr.: diffusivité magnétique
Fr.: inclinaison magnétique
In terrestrial magnetism, the angle that a → magnetic needle makes with the horizontal plane at any specific location. The angle of magnetic dip at the → magnetic poles of Earth is 90°. Also called → inclination and → dip.
Fr.: dipole magnétique
A system that generates a → magnetic field in which the field is considered to result from two opposite poles, as in the north and south poles of a magnet, much as an → electric field originates from a positive and a negative charge in an → electric dipole. A loop carrying an electric current also acts as a magnetic dipole. Magnetic dipoles experience a torque in the presence of magnetic fields. → dipole moment; → magnetic moment.