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| '''Plasma Modeling''' refers to solving [[equations of motion]] that describe the state of a [[plasma (physics)|plasma]]. It is generally coupled with [[Maxwell's Equations]] for [[electromagnetic field]]s or [[Poisson's Equation]] for electrostatic fields. There are several main types of plasma models: single particle, kinetic, fluid, hybrid kinetic/fluid, gyrokinetic and as system of many particles. | | Ed is what individuals call me and my spouse doesn't like it at all. For a whilst I've been in Alaska but I will have to transfer in a year or two. He is an information officer. To play lacross is some thing he would by no means give up.<br><br>My website: [http://help.ksu.edu.sa/node/65129 love psychics] |
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| ==Single Particle Description==
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| The single particle model describes the plasma as individual electrons and ions moving in imposed (rather than self-consistent) electric and magnetic fields. The motion of each particle is thus described by the [[Lorentz Force Law]].
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| In many cases of practical interest, this motion can be treated as the superposition of a relatively fast circular motion around a point called the [[guiding center]] and a relatively slow drift of this point.
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| ==Kinetic Description==
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| The kinetic model is the most fundamental way to describe a plasma, resultantly producing a [[distribution function]]
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| :<math>f(\vec{x},\vec{v},t)</math>
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| where the independent variables <math>\vec{x}</math> and <math>\vec{v}</math> are [[position (vector)|position]] and [[velocity]], respectively.
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| A kinetic description is achieved by solving the [[Boltzmann equation]] or, when the correct description of long-range [[Coulomb's law|Coulomb interaction]] is necessary, by the [[Vlasov equation]] which contains self-consistent collective electromagnetic field, or by the [[Fokker-Planck equation]], in which approximations have been used to derive manageable collision terms. The charges and currents produced by the distribution functions self-consistently determine the electromagnetic fields via [[Maxwell's equations]].
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| ==Fluid Description==
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| To reduce the complexities in the kinetic description, the fluid model describes the plasma based on macroscopic quantities (velocity moments of the distribution such as density, mean velocity, and mean energy). The equations for macroscopic quantities, called fluid equations, are obtained by taking velocity moments of the [[Boltzmann equation]] or the [[Vlasov equation]]. The fluid equations are not closed without the determination of transport coefficients such as mobility, [[diffusion coefficient]], averaged collision frequencies, and so on. To determine the transport coefficients, the velocity distribution function must be assumed/chosen. But this assumption can lead to a failure of capturing some physics.
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| ==Hybrid Kinetic/Fluid Description==
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| Although the kinetic model describes the physics accurately, it is more complex (and in the case of numerical simulations, more computationally intensive) than the fluid model. The hybrid model is a combination of fluid and kinetic models, treating some components of the system as a fluid, and others kinetically.
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| ==Gyrokinetic Description==
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| In the [[Gyrokinetics|gyrokinetic model]], which is appropriate to systems with a strong background magnetic field, the kinetic equations are averaged over the fast circular motion of the [[gyroradius]]. This model has been used extensively for simulation of [[tokamak]] plasma instabilities (for example, the [[GYRO]] and [[Gyrokinetic ElectroMagnetic]] codes), and more recently in astrophysical applications.
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| ==See also==
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| *[[List of plasma (physics) articles]]
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| ==References==
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| *{{cite book | author=Francis F. Chen | title=Introduction to Plasma Physics and Controlled Fusion, 2nd ed | publisher=Springer | year=2006 | isbn=0-306-41332-9 }}
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| *{{cite book | author=Nicholas Krall and Alvin Trivelpiece | title=Principles of Plasma Physics | publisher=San Francisco Press| year=1986 | isbn=0-911302-58-1 }}
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| *{{cite journal|last=Ledvina|first=S. A.|coauthors=Y.-J. Ma, E. Kallio|title=Modeling and Simulating Flowing Plasmas and Related Phenomena|journal=Space Science Reviews|year=2008|volume=139|doi=10.1007/s11214-008-9384-6}}
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| {{DEFAULTSORT:Plasma Modeling}}
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| [[Category:Plasma physics]]
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Ed is what individuals call me and my spouse doesn't like it at all. For a whilst I've been in Alaska but I will have to transfer in a year or two. He is an information officer. To play lacross is some thing he would by no means give up.
My website: love psychics