An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

Homepage

Number of Results: 145 Search : magnet
 magnetic tension   تنش ِ مغناتیسی   taneš-e meqnâtisiFr.: tension magnétique   In → magnetohydrodynamic (MHD) treatment of → plasmas, that component of the → Lorentz force which is directed toward the centre of curvature of the → magnetic field lines and thus acts to straighten out the field lines. The Lorentz force can be decomposed into two components orthogonal to the magnetic field: j× B = (B . ∇) B / μ0 - ∇ (B2 / 2μ0), where j is the → current density, μ0 is the → magnetic permeability of free space, and B is the → magnetic flux density. The left side term is the Lorentz force, the first term on the right side is the magnetic tension and the second term the → magnetic pressure.→ magnetic; → tension. magnetic vector potential   توند ِ برداری ِ مغناتیسی   tavand-e bordâri-ye meqnâtisiFr.: vecteur potentiel magnétique   A vector field A defined so that the → magnetic field  B is given by its → curl: B = ∇ x A.→ magnetic; → vector; → potential. magnetic-dipole radiation   تابش ِ دوقطبه‌ی ِ مغناتیسی   tâbeš-e doqotbe-ye meqnâtisi (#)Fr.: rayonnement du dipôle magnétique   Radiation emitted by a rotating magnet.→ magnetic; → dipole; → radiation. magnetics   مغناتیک   meqnâtikFr.: magnétisme   The study of magnetic phenomena, comprising magnetostatics and electromagnetism.→ magnetic; → -ics. magnetism   مغنات‌مندی   meqnâtmandiFr.: magnétisme   The science of magnetic phenomena, including the fields and forces produced by magnets and, more generally, by moving electric charges.N.L. magnetismus; → magnet + → -ism. Magnetism in Massive Stars (MiMeS)      MiMeSFr.: MiMeS   An international collaboration devoted to the study of the origin and physics of → magnetic fields in → massive stars. The project uses several observatories and a large number of telescopes equipped with → spectropolarimetric and → asteroseismologic instruments, including → HARPS, → HARPSpol, and → ESPaDOnS (Wade et al., 2016, MNRAS 456, 2).→ magnetism; → massive; → star. magnetization   مغناتش   meqnâtešFr.: magnétisation   1) General: The process of magnetizing or the state of being magnetized. 2) Electricity: The → magnetic moment per unit volume induced by an external magnetic field; measured in → amperes per meter.Verbal noun of → magnetize. magnetize   مغناتیدن   meqnâtidanFr.: magnétiser   To make a magnet of, or impart the properties of a magnet to.From → magnet + → -ize. magnetized   مغناتیده   meqnâtidéFr.: magnétisé   Having been made magnetic; magnetic properties imparted to.Past participle of → magnetize. magnetized plasma   پلاسمای ِ مغناتیده   pelâmâ-ye meqnâtidéFr.: plasma magnétisé   A plasma containing a magnetic field which is strong enough to change the path of charged particles. It can be a → collisional plasma or → noncollisional plasma.→ magnetized; → plasma. magnetized vacuum   خلأ ِ مغناتیده   xala'-e meqnâtidéFr.: vide magnétisé   Empty space influenced by very strong → magnetic field. Same as → birefringent vacuum.→ magnetized; → vacuum. magneto-   مغنات-، مغناتو-   meqnât-, meqnâto-Fr.: magnéto-, magnét-   The prefix form of → magnet, representing magnetic or magnetism in compound words, such as → magnetogram, → magnetohydrodynamics.→ magnet. magneto-asteroseismology   مغنات-اخترلرزه‌شناسی   meqnât-axtarlarzešenâsiFr.: magnéto-astérosismologie   Combined study of the large-scale → magnetic field (→ magnetometry) and → stellar pulsations (→ asteroseismology). Magneto-asteroseismology provides strong complementary diagnostics suitable for detailed stellar modeling and permits the determination of the → internal structure and conditions within → magnetic massive  → pulsators, for example the effect of magnetism on → mixing processes. More specifically, asteroseismology yields information on the → density, → composition, and → chemical mixing in multiple internal layers (depending on the number of studied frequencies). Additionally, when rotationally split pulsation modes are observed, the internal rotation profile can be retrieved. From magnetometry surface properties are determined, related to the → chemical composition, including → starspots, and the magnetic field, such as its geometry, obliquity, and strength. Magnetic studies also provide constraints about the → stellar wind geometry and the → circumstellar environment. Moreover, the stellar → rotation period period and the → angle of inclination toward the observer are also retrieved (Buysschaert et al., 2017, astro-ph/1709.02619). magnetocentrifugal acceleration   شتاب ِ مغنات-مرکزگریز   šetâb-e meqnât-markazgorizFr.: accelération magnetocentrifuge   The acceleration exerted on the plasma particles according to the → magnetocentrifugal model. magnetocentrifugal model   مدل ِ مغنات-مرکزگریز   model-e meqnât-markazgorizFr.: modèle magnétocentrifuge   A → magnetohydrodynamic model devised to account for the → bipolar jets and → outflows observed around → protostars. Basically, a → poloidal magnetic field is frozen into a rotating → accretion disk. If the angle between the magnetic field lines threading the disk and the rotation axis of the disk is larger than 30°, the plasma can be accelerated out of the accretion disk along the field lines. The field lines rotate at a constant → angular velocity, and as the gas moves outward along the field lines, it is accelerated by an increasing → centrifugal force (magnetocentrifugal acceleration). At some point, when the rotation velocity is about the same as the → Alfven velocity in the gas, the field lines get increasingly wound up by the inertia of the attached gas and a strong → toroidal magnetic field component is generated. The toroidal component is the main agent in collimating the flow into a direction along the → open magnetic field lines. The earliest version of the model was proposed by Blandford & Payne (1982, MNRAS 199, 883). It has two main versions: → X-wind and → disk wind models. See also → magnetorotational instability.→ magneto-; → centrifugal; → model. magnetogram   مغنات‌نگاشت   meqnâtnegâštFr.: magnétogramme   A graphic representation of solar magnetic field strengths and polarity.From → magneto- + → -gram. magnetohydrodynamic   مغنات-و-هیدروتوانیک   meqnâtohidrotavânikFr.: magnétohydrodynamique   Of or relating to → magnetohydrodynamics.→ magneto- + → hydrodynamic. magnetohydrodynamics (MHD)   مغنات-و-هیدروتوانیک   meqnâtohidrotavânikFr.: magnétohydrodynamique   The dynamics of an ionized plasma in the non-relativistic, collisional case. In this description, charge oscillations and high frequency electromagnetic waves are neglected. It is an important field of astrophysics since plasma is one of the commonest forms of matter in the Universe, occurring in stars, planetary magnetospheres, and interplanetary and interstellar space.From → magneto- + → hydrodynamics. magnetometer   مغنات‌سنج   meqnâtsanjFr.: magnétomètre   Any of a variety of devices used to measure the strength and direction of a magnetic field.From → magneto- + → -meter. magnetometry   مغنات‌سنجی   meqnârsanjiFr.: magnétométrie   The detection or measurement of a magnetic field, especially its strength and direction. See also → magnetometer.→ magneto-; → -metry.