In plasma physics, the Debye length, named after the Dutch physical chemist Peter Debye, is the scale over which mobile charge carriers (e.g. electrons) screen out electric fields in plasmas and other conductors. In other words, the Debye length is the distance over which significant charge separation can occur. A Debye sphere is a volume whose radius is the Debye length, in which there is a sphere of influence, and outside of which charges are screened. [see Keely's Outreach]

In space plasmas where the electron density is relatively low, the Debye length may reach macroscopic values, such as in the Magnetosphere, Solar wind, Interstellar medium and Intergalactic medium (see table):

Plasma	Density ne(m3)	Electron temperature T(K)	Magnetic field B(T)	Debye length λD(m)
Gas discharge	1016	104	--	10−4
Tokamak	1020	108	10	10−4
Ionosphere	1012	103	10−5	10−3
Magnetosphere	107	107	10−8	102
Solar core	1032	107	--	10−11
Solar wind	106	105	10−9	10
Interstellar medium	105	104	10−10	10
Intergalactic medium	1	106	--	105

Source: Chapter 19: The Particle Kinetics of Plasma http://www.pma.caltech.edu/Courses/ph136/yr2002/

Hannes Alfvén pointed out that: "In a low density plasma, localized space charge regions may build up large potential drops over distances of the order of some tens of the Debye lengths. Such regions have been called electric double layers. An electric double layer is the simplest space charge distribution that gives a potential drop in the layer and a vanishing electric field on each side of the layer. In the laboratory, double layers have been studied for half a century, but their importance in cosmic plasmas has not been generally recognized.". http://www.plasma-universe.com/Debye_length

See Also

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3.14 - Vortex Theory of Atomic Motions 13.04 - Atomic Subdivision atomic Atomic Cluster X-Ray Emission Atomic Clusters Atomic Force atomic mass atomic number atomic theory atomic triplet atomic weight Debye Continuum Debye length Debye length in a plasma Debye length in an electrolyte Debye Sphere diatomic Etheric Orbital Rotations Figure 13.06 - Atomic Subdivision Force-Atomic Formation of Atomic Clusters Inert Gas Interaction of Intense Laser Pulses with Atomic Clusters - Measurements of Ion Emission Simulations and Applications TD69.pdf InterAtomic Laser Cluster Interactions Law of Atomic Dissociation Law of Atomic Pitch Law of Oscillating Atomic Substances Law of Pitch of Atomic Oscillation Law of Variation of Atomic Oscillation by Electricity Law of Variation of Atomic Oscillation by Sono-thermism Law of Variation of Atomic Oscillation by Temperature Law of Variation of Atomic Pitch by Electricity and Magnetism Law of Variation of Atomic Pitch by Rad-energy Law of Variation of Atomic Pitch by Temperature Law of Variation of Pitch of Atomic Oscillation by Pressure Models of Laser Cluster Interactions monatomic Nanoplasma Plasma Plasma holes Quasi-neutrality Quasi-neutrality and Debye length Violation of quasi-neutrality