"ප්ලාස්මා (භෞතික විද්‍යාව)" හි සංශෝධන අතර වෙනස්කම්

In [[astrophysical]] plasmas, [[electric field screening|Debye screening]] prevents [[electric field]]s from directly affecting the plasma over large distances (ie. greater than the [[Debye length]]). But the existence of charged particles causes the plasma to generate and be affected by [[magnetic field]]s. This can and does cause extremely complex behavior, such as the generation of plasma double layers, an object which separates charge over a few tens of [[Debye length]]s. The dynamics of plasmas interacting with external and self-generated [[magnetic field]]s are studied in the [[academic discipline]] of [[magnetohydrodynamics]].

 

A plasma in which the magnetic field is strong enough to influence the motion of the charged particles is said to be magnetized. A common quantitative criterion is that a particle on average completes at least one gyration around the magnetic field before making a collision (ie. <span style="font-size:125%"><math>\omega_{ce}/\nu_{coll} > 1</math></span> where <span style="font-size:125%"><math>\omega_{ce}</math></span> is the "electron gyrofrequency" and <span style="font-size:125%"><math>\nu_{coll}</math></span> is the "electron collision rate"). It is often the case that the electrons are magnetized while the ions are not. Magnetized plasmas are ''[[anisotropic]]'', meaning that their properties in the direction parallel to the magnetic field are different from those perpendicular to it. While electric fields in plasmas are usually small due to the high conductivity, the electric field associated with a plasma moving in a magnetic field is given by '''E''' = -'''v''' x '''B''' (where '''E''' is the electric field, '''v''' is the velocity, and '''B''' is the magnetic field), and is not affected by [[Debye shielding]].<ref>Richard Fitzpatrick, ''Introduction to Plasma Physics'', [http://farside.ph.utexas.edu/teaching/plasma/lectures/node10.html Magnetized plasmas]</ref>