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Topic: Debye length


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In the News (Mon 17 Jun 19)

  
  The Thomas Group - PTCL, Oxford
This atmosphere of charge is called the ionic atmosphere and the distance 1/κ is often referred to as the radius of the ionic atnmosphere and/or the Debye length.
It is useful to remember that the Debye length is 10 nm for a 0.001 M solution of a 1:1 electrolyte.
This lowering is greater the shorter the Debye length and the greater the charges of the ions involved.
physchem.ox.ac.uk /~rkt/lectures/liqsolns/electrolyte_solutions.html   (1406 words)

  
 Peter Debye Summary
Debye was professor of theoretical physics at the University of Utrecht from 1912 until 1914, when he received the prestigious post of director of the theoretical branch of the Institute of Physics at the University of Göttingen.
During his year there, Debye studied the dipole moment of molecules, that is, its tendency to rotate in an external magnetic field, a property that is a function of the distribution of electric charge in (the polarity of) the molecule.
Debye was also awarded the 1936 Nobel Prize in chemistry for this research, although he is perhaps best known for his contribution to the theory of electrolytic dissociation, the Debye-Hückel theory, announced in 1923.
www.bookrags.com /Peter_Debye   (5229 words)

  
 Debye   (Site not responding. Last check: 2007-10-03)
Peter Debye (born Petrus Josephus Wilhelmus Debije) was born in Maastricht, Holland, on March 24, 1884, son of Wilhelmus and Maria Reumkens Dibje.
From 1934 to 1939 Debye was director of the prestigious Max Planck Institute in Berlin.
Debye's most treasured award is his bust, a gift of the natives of his birthplace, Maastricht, was there unveiled in his honor to adorn the town hall.
chem.ch.huji.ac.il /~eugeniik/history/debye.html   (2530 words)

  
 Debye length - Wikipedia, the free encyclopedia
In plasma physics, the Debye length, named after the Dutch physical chemist Peter Debye, is the scale over which mobile charge carriers (e.g.
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.
en.wikipedia.org /wiki/Debye_length   (282 words)

  
 The Plasma Tutorial
A Debye sphere is a sphere of radius one Debye length.
A Debye length is a typical length over which a charged particle's bare electric field has substantial influence.
So, the Debye sphere, which is a sphere with radius equal to the Debye length, centred on the charge, is a charged particle's typical "sphere of influence" on neighbouring plasma particles.
www.hmo.ac.za /old_site/Space_Physics/tut/tut.html   (1863 words)

  
 The Debye Length, Avon, Ohio   (Site not responding. Last check: 2007-10-03)
This distance, called a Debye length, is a measure of the distance over which an individual charged particle can exert an effect.
The Debye length is equal to (6.9 times the square root of (T/n))centimeters, where T is the temperature of the electrons in Kelvins and n(e) is the number of electrons per cubic centimeter.
For a body of particles to behave as a plasma, its dimensions must be large compared to the Debye length.
www.centuryinter.net /tjs11/school/debye.htm   (165 words)

  
 Debye shielding
Not surprisingly, the length-scale associated with such shielding is the Debye length.
Actually, Debye shielding remains statistically significant, and physical, in the opposite limit in which the cloud is barely populated.
In the latter case, it is the probability of observing charged particles within a Debye length of the perturbing charge which is modified.
farside.ph.utexas.edu /teaching/plasma/lectures/node7.html   (247 words)

  
 Springer Online Reference Works
Outside the sphere of radius equal to the Debye length, the field is shielded as a result of the polarization of the surrounding medium.
The concept of the Debye length was introduced by P.
Debye in connection with his studies on electrolytic phenomena.
eom.springer.de /d/d030360.htm   (207 words)

  
 Analysis of the derived functions
A plot of the Debyer layer, the potential and the concentration profile of a negative ion is presented in figure 2.4, 2.5 and 2.6.
The Debye length is approximately the length of the diffusion layer at low potentials.
Above 0.25 V the length becomes shorter and the gradient at the boundary is very steep.
www.student.dtu.dk /~s991799/reporthoved/node15.html   (368 words)

  
 Debye sheath - Wikipedia, the free encyclopedia
The Debye sheath (also electrostatic sheath) is a layer in a plasma which has a greater density of positive ions, and hence an overall excess positive charge, that balance an opposite negative charge in the surface of a material in which it is in contact.
The thickness of such a layer is several Debye lengths thick, a value whose size depends on various characteristics of plasma (eg.
A Debye sheath arising in a plasma because the electrons usually have a temperature on the order of or greater than that of the ions and are much lighter.
en.wikipedia.org /wiki/Debye_sheath   (1234 words)

  
 PIC Plasma Simulation
In particular, a plasma with a Debye length which is less than the mesh spacing cannot be accurately simulated for many multiples of the electron plasma frequency.
The reason for this is that the Debye length is the distance over which charge separation effects can occur in a plasma, and if the mesh spacing is larger than this, these effects will not be reflected in the fields which are calculated and assigned to the mesh points.
The mesh spacing should not be very much greater than the Debye length, so that the potentials set up by charge separation can be resolved.The timestep should be less than the period of the plasma frequency, so that the particle oscillations are faithfully reproduced.
www.geocities.com /letapk/pic.html   (3311 words)

  
 [No title]
The results yield experimental values for the dust plasma frequency, charge, Debye length, and damping rate, and support the applicability of fluid-based dispersion relations to strongly-coupled dusty plasmas, which has been a controversy.
Calculations of the shielding length and charge based on theoretical models are not practical, since these quantities depend on the ion flow conditions around a grain and plasma non-neutrality in the electrode sheath, which cannot be measured readily.
The orientational correlation length [[xi]]6 is from a fit to the correlation function g6(r) for the static structure.
dusty.physics.uiowa.edu /~goree/papers/PRL_wave_resubmitted.html   (2741 words)

  
 Debye length?
The definition of Debye length is the length in which mobile charge carriers screen out the external electric field.
In the context of a plasma, L is probably a characteristic length, as in the mean distance between successive particle collisions, for example.
I assume the module is indicating that the distance between successive collisions of particles is much greater than the Debye length.
www.physicsforums.com /showthread.php?t=75706   (400 words)

  
 Division of Plasma Physics
But in a plasma, the field is almost completely shielded beyond a distance called the Debye length.
In fact, it is only when the Debye shielding length is smaller than the cloud of charged particles-smaller, for instance, than the laboratory chamber in which they're produced-that physicists strictly refer to the collective ensemble as a plasma.
The key, however, is the notion that particles in a plasma act in concert, behaving as a collective beast that seems to have a mind of its own.
www.apsdpp.org /plasma_brochure/page4.html   (508 words)

  
 The Future in Energy is Through Plasma Research
Any displacement of the electrons relative to the ions over a distance of the order of a Debye length gives rise to strong electrostatic fields that accelerate the electrons back toward the ions.
Upon reaching their original positions, the electrons will have kinetic energy equal to the potential energy acquired in their displacement and will consequently overshoot, continuing to oscillate about an equilibrium position until this energy is dissipated.
This balance can occur only if the average velocity of the approaching electrons is reduced and that of the approaching positive ions increased by the formation of a layer of net negative charge near the object and a layer of net positive charge one Debye length into the plasma.
www.infoimagination.org /ps/plasma   (1890 words)

  
 Bond Graph Modelling of Electrolyte Gel
The characteristic length of gel element is much greater that the Debye length.
Such "local" electric field, which acts in the scale of a few Debye length, is quite large and it is rather difficult to induce charge separation in macroscopic scale.
Therefore, this simulation result justifies the assumption of quasi-equilibrium between the surrounding bath and the region near the interface (assuming the typical gel/membrane are thicker than the Debye length by several orders of magnitude).
www.ai.mit.edu /projects/muscle/papers/elegel/ele.htm   (3337 words)

  
 Debye Length and Double-Layer Forces in Polyelectrolyte Solutions
We report experimental results and a theoretical analysis of the Debye length in aqueous solutions of nonadsorbing polyelectrolytes.
We use the mean-field Poisson-Boltzmann theory to theoretically predict the effective Debye length and double-layer force under such conditions and compare the predictions with the experimental results.
The comparison gives excellent agreement and shows that the effective Debye length is determined solely by the monovalent ions in the solution.
pubs.acs.org /cgi-bin/abstract.cgi/mamobx/2002/35/i06/abs/ma011893y.html   (209 words)

  
 Ion Flux
In the case of a collisional sheath (more appropriate for many CVD processes at > 1 Torr), the sheath velocity is reduced relative to the Bohm velocity by the ratio of the ion mean free path to the Debye length.
The Debye length is the characteristic length over which the plasma electrons screen an applied potential; numerically it is approximately
For a 4 eV plasma with density of 1E10/cm3, the debye length is 0.014 cm or 140 microns.
www.timedomaincvd.com /CVD_Fundamentals/plasmas/ion_flux.html   (672 words)

  
 Stanford Microfluidics Laboratory
EO pump devices require the interaction of physical phenomena across a wide range of length scales.
When external electric field is applied, bulk motion of an electrolyte caused by Coulombic forces acting on ions in the electric double layer.
The typical length scale for the Debye length is on the order of 1 nm, depending on the ionic contents in the liquids.
microfluidics.stanford.edu /eopump.htm   (1186 words)

  
 Question- difference between plasma and ionization?
One general criterion for a material to be classified as a plasma is the existence of Debye shielding and the presence of a large number of electrons/ions in a "debye sphere."
The density gives you the plasma frequency and divide that into the thermal speed to obtain the debye length.
Cube the debye length and multiply it by the number density to find the number of electrons in a debye sphere.
www.physicsforums.com /showthread.php?t=50886   (322 words)

  
 2.4.2 Debye Length
As you might know, the Debye length is a crucial material parameter not only in all questions concerning ionic conducitvity (the field of "Ionics"), but whenever the carrier concentration is not extremely large (i.e.
If you are some Debye lengths away from these fixed charges, you will not "see" them anymore; their effect on the equilibrium carrier distribution then is vanishingly small.
In other words, after you moved about one Debye length away from the surplus charge, its effects on the mobile charges of the material are no longer felt.
www.tf.uni-kiel.de /matwis/amat/elmat_en/kap_2/backbone/r2_4_2.html   (1194 words)

  
 Locating the Micellar Shear Plane and Its Relationship with the Debye Screening Length
The shear plane and shear potential of suspended nanoscale particles such as micelles and colloids are important parameters; however, reports detailing their determination are scarce and are restricted to relatively large colloidal and polymeric particles.
In addition, for charged particles such as colloids and anionic or cationic micelles, the relationship between the Debye screening length and the location of the shear plane has not yet been established.
In addition, estimations of the Debye screening length at the micellar charged surface allow direct comparison with the shear plane thickness.
pubs.acs.org /cgi-bin/abstract.cgi/jpcbfk/1999/103/i24/abs/jp9843914.html   (279 words)

  
 Conventional Fusion FAQ Glossary Part 4/26 (D)
Debye, Peter Joseph: Physical chemist, studied behavior of conductive solutions (plasmas have some similar behaviors).
Its characteristic thickness is the Debye length, and it is caused by Debye shielding of the negative surface charge resulting from electrons flowing to the surface much faster (initially) than the ions.
The net result is an additional negative (positive) charge density which cancels the effect of the initial charge at distances large compared to the Debye length.
www.faqs.org /faqs/fusion-faq/glossary/d   (1854 words)

  
 [No title]
We note that the Debye length can be expressed in terms of the plasma frequency as  EMBED Equation.3  where vte is the mean thermal speed  EMBED Equation.3 .
The appropriate formulation is to transform the time, length scale and fields according to the Lorentz transformation from one frame to another, resulting in two different expressions for parallel and perpendicular directions.
Plasma Sheaths A consequence of Debye shielding is the formation of a boundary layer, called a sheath, at the interface between the plasma and any surface, conducting or non-conducting.
uspas.fnal.gov /programs/w&m/Lecture1.doc   (2440 words)

  
 CMPD - Center for Multiscale Plasma Dynamics (anomalous resistivity research plan, LAPD)
In the LAPD the Debye length is 16-30 microns.
There are several geometries of the sensor but all contain detectors which are much smaller than the Debye length, and are spaced 50-100 microns apart.
With twelve fast channels we can study the propagation of structures as small as the Debye length as well as their statistical properties.
www.cscamm.umd.edu /cmpd/anomalous_plan_lapd.htm   (1008 words)

  
 Hugo's Basic Plasma Physics Text
The Debye length describes the range of an electric potential inside a plasma, which is much smaller than the range in vacuum.
A more heuristic deviation of the Debye length is the following: small charge separations arise as a result of thermal fluctuations.
In the last step the Debye length has been introduced as the upper limit of the Coulomb potential to take into account Debye shielding, thus removing the divergence.
www.rijnh.nl /users/deblank/lectures/zy/tbasic.html   (1871 words)

  
 plasma interactions   (Site not responding. Last check: 2007-10-03)
The effect alters the usual potential in the vicinity of the particle, causing it to decrease exponentially with scale length of the Debye length.
This will be important in detailing emission by collisions of charged particles, which would diverge logarithmically except for this cutoff in the influence of electrostatic interaction.
An ampere is defined as a quantity of current which causes a transverse force per unit length of 2 x 10
www.aoc.nrao.edu /~jweather/physics425/node11.html   (306 words)

  
 Definition of a Plasma   (Site not responding. Last check: 2007-10-03)
The technical definition of a plasma is simply this: the number of charged particles in a Debye sphere is large compared to unity.
What we are interested in is the number of particles which feel a force due to the charge of any given particle, as opposed to what they feel due to the sum of the electric fields exerted collectively by all the other particles.
The sphere containing the volume within one Debye length of a given particle is called its ``Debye sphere''.
www.ipp.mpg.de /~bds/phys/plasma-def.html   (218 words)

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