Plasma physics
 This article is about plasma in the sense of an ionized gas. For other uses of the term, such as blood plasma, see plasma (disambiguation).
In physics and chemistry, a plasma is an ionized gas, and is usually considered to be a distinct phase of matter. "Ionized" in this case means that at least one electron has been removed from a significant fraction of the molecules. The free electric charges make the plasma electrically conductive so that it couples strongly to electromagnetic fields. This fourth state of matter was first identified by Sir William Crookes in 1879 and dubbed "plasma" by Irving Langmuir in 1928, because it reminded him of a blood plasma [Ref].
Contents
Common plasmas
Plasmas are the most common phase of matter. The entire visible universe outside the Solar System is plasma, since all we can see are stars. Since the space between the stars is filled with a plasma, although a very sparse one (see interstellar and intergalactic medium), essentially the entire volume of the universe is plasma. In the Solar System, the planet Jupiter accounts for most of the nonplasma, only about 0.1% of the mass and 10^{15} of the volume within the orbit of Pluto.
Commonly encountered forms of plasma include:
 Artificially produced
 Inside fluorescent lamps (low energy lighting), neon signs
 Rocket exhaust
 The area in front of a spacecraft's heat shield during reentry into the atmosphere
 Fusion energy research
 The electric arc in an arc lamp or an arc welder
 Plasma ball (sometimes called a plasma sphere or plasma globe)
 Earth plasmas
 Flames (ie. fire)
 Lightning
 The ionosphere
 The polar aurorae
 Space and astrophysical
 The Sun and other stars (which are plasmas heated by nuclear fusion)
 The solar wind
 The Interplanetary medium (the space between the planets)
 The Interstellar medium (the space between star systems)
 The Intergalactic medium (the space between galaxies)
 The IoJupiter fluxtube
 Accretion disks
 Interstellar nebulae
Characteristics
The term plasma is generally reserved for a system of charged particles large enough to behave collectively. Even a partially ionized gas in which as little as 1% of the particles are ionized can have the characteristics of a plasma (i.e. respond to magnetic fields and be highly electrically conductive).
In technical terms, the typical characteristics of a plasma are:
 Debye screening lengths that are short compared to the physical size of the plasma.
 Large number of particles within a sphere with a radius of the Debye length.
 Mean time between collisions usually is long when compared to the period of plasma oscillations.
Plasma scaling
Plasmas and their characteristics exist over a wide range of scales (ie. they are scaleable over many orders of magnitude). The following chart deals only with conventional atomic plasmas and not other exotic phenomena, such as, quark gluon plasmas:
Typical plasma scaling ranges: orders of magnitude (OOM)  
Characteristic  Terrestrial plasmas  Cosmic plasmas 
Size in metres (m)  10^{6} m (lab plasmas) to: 10^{2} m (lightning) (~8 OOM)  10^{6} m (spacecraft sheath) to 10^{25} m (intergalactic nebula) (~31 OOM) 
Lifetime in seconds (s)  10^{12} s (laserproduced plasma) to: 10^{7} s (fluorescent lights) (~19 OOM)  10^{1} s (solar flares) to: 10^{17} s (intergalactic plasma) (~17 OOM) 
Density in particles per cubic metre  10^{7} to: 10^{21} (inertial confinement plasma)  10^{30} (stellar core) to: 10^{0} (i.e., 1) (intergalactic medium) 
Temperature in kelvins (K)  ~0 K (Crystalline nonneutral plasma[2]) to: 10^{8} K (magnetic fusion plasma)  10^{2} K (aurora) to: 10^{7} K (Solar core) 
Magnetic fields in teslas (T)  10^{4} T (Lab plasma) to: 10^{3} T (pulsedpower plasma)  10^{12} T (intergalactic medium) to: 10^{7} T (Solar core) 
Temperatures
The defining characteristic of a plasma is ionization. Although ionization can be caused by UV radiation, energetic particles, or strong electric fields, (processes that tend to result in a nonMaxwellian electron distribution function), it is more commonly caused by heating the electrons in such a way that they are close to thermal equilibrium so the electron temperature is relatively welldefined. Because the large mass of the ions relative to the electrons hinders energy transfer, it is possible for the ion temperature to be very different from (usually lower than) the electron temperature.
The degree of ionization is determined by the electron temperature relative to the ionization energy (and more weakly by the density) in accordance with the Saha equation. If only a small fraction of the gas molecules are ionized (for example 1%), then the plasma is said to be a cold plasma, even though the electron temperature is typically several thousand degrees. The ion temperature in a cold plasma is often near the ambient temperature. Because the plasmas utilized in plasma technology are typically cold, they are sometimes called technological plasmas. They are often created by using a very high electric field to accelerate electrons, which then ionize the atoms. The electric field is either capacitively or inductively coupled into the gas by means of a plasma source, e.g. microwaves. Common applications of cold plasmas include plasmaenhanced chemical vapor deposition, plasma ion doping, and reactive ion etching.
A hot plasma, on the other hand, is nearly fully ionized. This is what would commonly be known as the "fourthstate of matter". The Sun is an example of a hot plasma. The electrons and ions are more likely to have equal temperatures in a hot plasma, but there can still be significant differences.
Densities
Next to the temperature, which is of fundamental importance for the very existence of a plasma, the most important property is the density. The word "plasma density" by itself usually refers to the electron density, that is, the number of free electrons per unit volume. The ion density is related to this by the average charge state Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \langle Z\rangle} of the ions through Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n_e=\langle Z\rangle n_i} . (See quasineutrality below.) The third important quantity is the density of neutrals Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n_0} . In a hot plasma this is small, but may still determine important physics. The degree of ionization is Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n_i/(n_0+n_i)} .
Potentials
Since plasmas are very good conductors, electric potentials play an important role. The potential as it exists on average in the space between charged particles, independent of the question of how it can be measured, is called the plasma potential or the space potential. If an electrode is inserted into a plasma, its potential will generally lie considerably below the plasma potential due to the development of a Debye sheath. Due to the good electrical conductivity, the electric fields in plasmas tend to be very small, although where double layers are formed, the potential drop can be large enough to accelerate ions to relativistic velocities and produce synchrotron radiation such as xrays and gamma rays. This results in the important concept of quasineutrality, which says that, on the one hand, it is a very good approximation to assume that the density of negative charges is equal to the density of positive charges (Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n_e=\langle Z\rangle n_i} ), but that, on the other hand, electric fields can be assumed to exist as needed for the physics at hand.
The magnitude of the potentials and electric fields must be determined by means other than simply finding the net charge density. A common example is to assume that the electrons satisfy the Boltzmann relation, Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n_e \propto e^{e\Phi/k_BT_e}} . Differentiating this relation provides a means to calculate the electric field from the density: Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \vec{E} = (k_BT_e/e)(\nabla n_e/n_e)} .
It is, of course, possible to produce a plasma that is not quasineutral. An electron beam, for example, has only negative charges. The density of a nonneutral plasma must generally be very low, or it must be very small, otherwise it will be dissipated by the repulsive electrostatic force.
In astrophysical plasmas, Debye screening prevents electric fields 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 fields. This can and does cause extremely complex behavior, such as the generation of plasma double layers, an object that separates charge over a few tens of Debye lengths. The dynamics of plasmas interacting with external and selfgenerated magnetic fields are studied in the academic discipline of magnetohydrodynamics.
In contrast to the gas phase
Plasma is often called the fourth state of matter. It is distinct from the three lowerenergy phases of matter; solid, liquid, and gas, although it is closely related to the gas phase in that it also has no definite form or volume. There is still some disagreement as to whether a plasma is a distinct state of matter or simply a type of gas. Most physicists consider a plasma to be more than a gas because of a number of distinct properties including the following:
Property  Gas  Plasma 
Electrical Conductivity  Very low 
Very high

Independently acting species  One  Two or three Electrons, ions, and neutrals can be distinguished by the sign of their charge so that they behave independently in many circumstances, having different velocities or even different temperatures, leading to new types of waves and instabilities, among other things 
Velocity distribution  Maxwellian  May be nonMaxwellian Whereas collisional interactions always lead to a Maxwellian velocity distribution, electric fields influence the particle velocities differently. The velocity dependence of the Coulomb collision cross section can amplify these differences, resulting in phenomena like twotemperature distributions and runaway electrons. 
Interactions  Binary Twoparticle collisions are the rule, threebody collisions extremely rare. 
Collective Each particle interacts simultaneously with many others. These collective interactions are about ten times more important than binary collisions. 
Complex plasma phenomena
Plasma may exhibit complex behaviour. And just as plasma properties scale over many orders of magnitude (see table above), so do these complex features. Many of these features were first studied in the laboratory, and in more recent years, have been applied to, and recognised throughout the universe. Some of these features include:
 Filamentation, the striations or "stringy things" seen in a "plasma ball", the aurora, lightning, and nebulae. They are caused by larger current densities, and are also called magnetic ropes or plasma cables.
 Double layers, localised charge separation regions that have a large potential difference across the layer, and a vanishing electric field on either side. Double layers are found between adjacent plasmas regions with different physical characteristics, and can accelerate ions and produce synchrotron radiation (such as xrays and gamma rays).
 Birkeland currents, a magneticfieldaligned electric current, first observed in the Earth's aurora, and also found in plasma filaments.
 Circuits. Birkeland currents imply electric circuits, that follow Kirchhoff's circuit laws. Circuits have a resistance and inductance, and the behaviour of the plasma depends on the entire circuit. Such circuits also store inductive energy, and should the circuit be disrupted, for example, by a plasma instability, the inductive energy will be released in the plasma.
 Cellular structure. Plasma double layers may separate regions with different properties such as magnetization, density, and temperature, resulting in celllike regions. Examples include the magnetosphere, heliosphere, and heliospheric current sheet.
 Critical ionization velocity in which the relative velocity between an ionized plasma and a neutral gas, may cause further ionization of the gas, resulting in a greater influence of electomagnetic forces.
Mathematical descriptions
Plasmas may be usefully described with various levels of detail. However the plasma itself is described, if electric or magnetic fields are present, then Maxwell's equations will be needed to describe them. The coupling of the description of a conductive fluid to electromagnetic fields is known generally as magnetohydrodynamics, or simply MHD.
Fluid
The simplest possibility is to treat the plasma as a single fluid governed by the Navier Stokes Equations. A more general description is the twofluid picture, where the ions and electrons are considered to be distinct.
Kinetic
For some cases the fluid description is not sufficient. Kinetic models include information on distortions of the velocity distribution functions with respect to a MaxwellBoltzmann distribution. This may be important when currents flow, when waves are involved, or when gradients are very steep.
Particleincell
Particleincell (PIC) models include kinetic information by following the trajectories of a large number of individual particles. Charge and current densities are determined by summing the particles in cells which are small compared to the problem at hand but still contain many particles. The electric and magnetic fields are found from the charge and current densities with appropriate boundary conditions. PIC codes for plasma applications were developed at Los Alamos National Laboratory in the 1950's. Although often more calculationally intensive than alternative models, they are relatively easy to understand and program and can be very general.
Fundamental plasma parameters
All quantities are in Gaussian cgs units except temperature expressed in eV and ion mass expressed in units of the proton mass Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \mu = m_i/m_p} ; Z is charge state; k is Boltzmann's constant; K is wavelength; γ is the adiabatic index; ln Λ is the Coulomb logarithm.
Frequencies
 electron gyrofrequency, the angular frequency of the circular motion of an electron in the plane perpendicular to the magnetic field:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \omega_{ce} = eB/m_ec = 1.76 \times 10^7 B \mbox{rad/s}}
 ion gyrofrequency, the angular frequency of the circular motion of an ion in the plane perpendicular to the magnetic field:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \omega_{ci} = eB/m_ic = 9.58 \times 10^3 Z \mu^{1} B \mbox{rad/s}}
 electron plasma frequency, the frequency with which electrons oscillate when their charge density is not equal to the ion charge density (plasma oscillation):
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \omega_{pe} = (4\pi n_ee^2/m_e)^{1/2} = 5.64 \times 10^4 n_e^{1/2} \mbox{rad/s}}
 ion plasma frequency:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \omega_{pe} = (4\pi n_iZ^2e^2/m_i)^{1/2} = 1.32 \times 10^3 Z \mu^{1/2} n_i^{1/2} \mbox{rad/s}}
 electron trapping rate
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \nu_{Te} = (eKE/m_e)^{1/2} = 7.26 \times 10^8 K^{1/2} E^{1/2} \mbox{s}^{1}}
 ion trapping rate
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \nu_{Ti} = (ZeKE/m_i)^{1/2} = 1.69 \times 10^7 Z^{1/2} K^{1/2} E^{1/2} \mu^{1/2} \mbox{s}^{1}}
 electron collision rate
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \nu_e = 2.91 \times 10^{6} n_e\,\ln\Lambda\,T_e^{3/2} \mbox{s}^{1}}
 ion collision rate
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \nu_i = 4.80 \times 10^{8} Z^4 \mu^{1/2} n_i\,\ln\Lambda\,T_i^{3/2} \mbox{s}^{1}}
Lengths
 Electron thermal de Broglie wavelength, approximate average de Broglie wavelength of electrons in a plasma:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \Lambda_e= \sqrt{\frac{h^2}{2\pi m_ekT_e}}= 6.919\times 10^{8}\,T_e^{1/2}\,\mbox{cm}}
 classical distance of closest approach, the closest that two particles with the elementary charge come to each other if they approach headon and each have a velocity typical of the temperature, ignoring quantummechanical effects:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle e^2/kT=1.44\times10^{7}\,T^{1}\,\mbox{cm}}
 electron gyroradius, the radius of the circular motion of an electron in the plane perpendicular to the magnetic field:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle r_e = v_{Te}/\omega_{ce} = 2.38\,T_e^{1/2}B^{1}\,\mbox{cm}}
 ion gyroradius, the radius of the circular motion of an ion in the plane perpendicular to the magnetic field:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle r_i = v_{Ti}/\omega_{ci} = 1.02\times10^2\,\mu^{1/2}Z^{1}T_i^{1/2}B^{1}\,\mbox{cm}}
 plasma skin depth, the depth in a plasma to which electromagnetic radiation can penetrate:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle c/\omega_{pe} = 5.31\times10^5\,n_e^{1/2}\,\mbox{cm}}
 Debye length, the scale over which electric fields are screened out by a redistribution of the electrons:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \lambda_D = (kT/4\pi ne^2)^{1/2} = 7.43\times10^2\,T^{1/2}n^{1/2}\,\mbox{cm}}
Velocities
 electron thermal velocity, typical velocity of an electron in a MaxwellBoltzmann distribution:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle v_{Te} = (kT_e/m_e)^{1/2} = 4.19\times10^7\,T_e^{1/2}\,\mbox{cm/s}}
 ion thermal velocity, typical velocity of an ion in a MaxwellBoltzmann distribution:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle v_{Ti} = (kT_i/m_i)^{1/2} = 9.79\times10^5\,\mu^{1/2}T_i^{1/2}\,\mbox{cm/s}}
 ion sound velocity, the speed of the longitudinal waves resulting from the mass of the ions and the pressure of the electrons:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle c_s = (\gamma ZkT_e/m_i)^{1/2} = 9.79\times10^5\,(\gamma ZT_e/\mu)^{1/2}\,\mbox{cm/s}}
 Alfven velocity, the speed of the waves resulting from the mass of the ions and the restoring force of the magnetic field:
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle v_A = B/(4\pi n_im_i)^{1/2} = 2.18\times10^{11}\,\mu^{1/2}n_i^{1/2}B\,\mbox{cm/s}}
Dimensionless
 square root of electron/proton mass ratio
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle (m_e/m_p)^{1/2} = 2.33\times10^{2} = 1/42.9}
 number of particles in a Debye sphere
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle (4\pi/3)n\lambda_D^3 = 1.72\times10^9\,T^{3/2}n^{1/2}}
 Alven velocity/speed of light
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle v_A/c = 7.28\,\mu^{1/2}n_i^{1/2}B}
 electron plasma/gyrofrequency ratio
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \omega_{pe}/\omega_{ce} = 3.21\times10^{3}\,n_e^{1/2}B^{1}}
 ion plasma/gyrofrequency ratio
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \omega_{pi}/\omega_{ci} = 0.137\,\mu^{1/2}n_i^{1/2}B^{1}}
 thermal/magnetic energy ratio
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \beta = 8\pi nkT/B^2 = 4.03\times10^{11}\,nTB^{2}}
 magnetic/ion rest energy ratio
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle B^2/8\pi n_im_ic^2 = 26.5\,\mu^{1}n_i^{1}B^2}
Miscellaneous
 Bohm diffusion coefficient
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle D_B = (ckT/16eB) = 6.25\times10^6\,TB^{1}\,\mbox{cm}^2/\mbox{s}}
 transverse Spitzer resistivity
 Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \eta_\perp = 1.15\times10^{14}\,Z\,\ln\Lambda\,T^{3/2}\,\mbox{s} = 1.03\times10^{2}\,Z\,\ln\Lambda\,T^{3/2}\,\Omega\,\mbox{cm}}
Fields of active research
 Plasma theory
 Plasma equilibria and stability
 Plasma interactions with waves and beams
 Guiding center
 adiabatic invariant
 Debye sheath
 Coulomb collision
 Plasmas in nature
 The Earth's ionosphere
 Space plasmas, e.g. Earth's plasmasphere (an inner portion of the magnetosphere dense with plasma)
 plasma cosmology
 Plasma sources
 Plasma diagnostics
 Plasma applications
 Fusion power
 Magnetic fusion energy (MFE)  tokamak, stellarator, reversed field pinch, magnetic mirror, dense plasma focus
 Inertial fusion energy (IFE) (also Inertial confinement fusion  ICF)
 Plasmabased weaponry
 Industrial plasmas
 Fusion power
See also
 Magnetohydrodynamics
 Electric field screening
 List of plasma physicists
 Large Helical Device
 Important publications in plasma physics
External links
 Plasmas: the Fourth State of Matter
 Plasma Science and Technology
 Plasma on the Internet comprehensive list of plasma related links.
 Introduction to Plasma Physics: a graduate level lecture course given by Richard Fitzpatrick
 An overview of plasma links and applications
 NRL Plasma Formulary online (or an html version)
 Plasma Coalition page
 Plasma Material Interaction
 How to build a Stable Plasmoid at One Atmosphere (requires preignition)
 How to build a Stable Plasmoid with this Enhanced Generator (selfigniting)
 How to make a glowing ball of plasma in your microwave with a grape
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