An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 3 Search : magnetohydrodynamics (MHD)
ideal magnetohydrodynamics (MHD)
  مغنات-و-هیدروتوانیک ِ آرمانی، ~ مینه‌وار   
meqnâtohidrotavânik-e ârmâni, ~ minevâr

Fr.: magnétohydrodynamique idéale   

Magnetohydrodynamics of a → plasma with very large (infinite) → conductivity. In this condition, → Ohm's law reduces to E = -v × B, where E represents → electric field, B → magnetic field, and v the → fluid velocity. Ideal MHD is the simplest model to describe the dynamics of plasmas immersed in a magnetic field. It is concerned with → one-fluid magnetohydrodynamics and neglects → resistivity. This theory treats the plasma composed of many charged particles with locally neutral charge as a continuous single → fluid. Ideal MHD does not provide information on the velocity distribution and neglects the physics relating to wave-particle interactions, as does the two-fluid theory as well. It does have the advantage that the macroscopic dynamics of the → magnetized plasma can be analyzed in realistic three-dimensional geometries (K. Nishikawa & M. Wakatani, 2000, Plasma Physics, Springer). See also → non-ideal magnetohydrodynamics.

ideal; → magnetohydrodynamics.

magnetohydrodynamics (MHD)
  مغنات-و-هیدروتوانیک   
meqnâtohidrotavânik

Fr.: 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.

non-ideal magnetohydrodynamics (MHD)
  مغنات-و-هیدروتوانیک ِ نا-آرمانی، ~ نا-مینه‌وار   
meqnâtohidrotavânik-e nâ-ârmâni, ~ nâ-minevâr

Fr.: magnétohydrodynamique non idéale   

A → magnetohydrodynamics approach dealing with → plasmas which is an improvement with respect to → ideal magnetohydrodynamics. Non-ideal magnetohydrodynamics allows for a drift between particles, redistributing the → magnetic flux and acting on both the → angular momentum and magnetic flux conservation issues.

non-ideal; → magnetohydrodynamics.