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A dusty plasma is a plasma containing nanometer or micrometer-sized particles suspended in it. Dust particles may be charged and the plasma and particles behave as a plasma  , following electromagnetic laws for particle up to about 10 nm (or 100 nm if large charges are present). Dust particles may acrete into larger particles resulting in "grain plasmas".
Additional recommended knowledge
Dusty plasmas are encountered in:
Dusty plasmas are interesting because presence of particles significantly alters the charged particle equilibrium leading to different phenomena. It is field of current research. Electrostatic coupling between the grains can vary over a wide range so that the states of the dusty plasma can change from weakly coupled (gaseous) to crystalline. Such plasmas are of interest as a non-Hamiltonian system of interacting particles and as a means to study generic fundamental physics of self-organization, pattern formation, phase transitions, and scaling.
The temperature of dust in a plasma may be quite different from its environment. For example:
The electric potential of dust particles is typically 1–10 V (positive or negative). The potential is usually negative because the electrons are more mobile than the ions. The physics is essentially that of a Langmuir probe that draws no net current, including formation of a Debye sheath with a thickness of a few times the Debye length. If the electrons charging the dust grains are relativistic, then the dust may charge to several kilovolts . Field emission, which tends to reduce the negative potential, can be important due to the small size of the particles. The photoelectric effect and the impact of positive ions may actually result in a positive potential of the dust particles.
The motion of solid particles in a plasma follows the momentum equation for ions and electrons:
where m, q are the mass and charge of the particle, g is the gravitation acceleration, mvcv is due to viscosity, and f respresents all other forces including radiation pressure. q (E + v x B) is the Lorentz force, where E is the electric field, v is the velocity and B is the magnetic field.
Then depending in the size of the particle, there are four categories:
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Dusty_plasma". A list of authors is available in Wikipedia.|