Questions tagged [debye-length]

The Debye length is the distance over which significant charge separation can occur in a conductive material or plasma due to a variety of effects.

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Plasma physics when plasma conditions don't apply

I've started to look into the field of plasma physics and I saw that not any gas of charges can be considered a plasma. There are 3 main conditions for something to be considered a plasma if I ...
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Why Debye shielding occur in plasma?

Why Debye shielding occur in plasma when we introduce a test charge? Does Debye shielding depends on test charge When it is introduced in plasma?
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Screened Coulomb potential in Debye-Huckel theory

I am rather confused about the meaning of the screened Coulomb potential in the Debye-Huckel theory. The potential of a unit charge inside an electrolyte takes the form $$\phi_{DH}(r) = \frac{ e^{-\...
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157 views

Physical meaning of Debye length

In plasma physics, what Debye length should represent in practice? From what I understood it's the maximum characteristic distance within which separate charges can be present in the internal space ...
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Debye length for a debye shield

I understand debye length and even the concept of debye shielding, but quantitatively I'm a little confused. If the debye shield has a potential of $$\Phi=\frac{q}{4\pi\epsilon_{0}r}\exp\left({\frac{-...
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Can't verify solution to Debye-Huckel equation

In the derivation of Debye length (https://en.wikipedia.org/wiki/Debye_length), the Debye-Huckel equation for a neutral system is $\nabla^2 \Phi(r) = \frac{\Phi(r)}{\lambda_D^2} - \frac{Q \delta^3(\...
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Boltzmann distribution of electrons at thermal equilibrium in a plasma

In Chen's Introduction to Plasma Physics and Controlled Fusion, it says the following during the discussion of Debye shielding: However the last equation tells me that the electron density $n_e$ will ...
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336 views

What Debye length should be used in plasma?

In short Which expression should be used: (1) or (2)? At length Definition of the Debye length $r_D$ is following: $$r_D=\left( \sum_{j}\frac{4\pi q_j^2 n_j}{kT_j} \right)^{-\frac{1}{2}}$$ It is ...
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Why take macroscopic average of electric field over length scale smaller then the Debye length?

In Landau and Lifshitz volume 10 pg117 the authors say that the electric and magnetic fields $\vec E$ and $\vec B$ are averaged over regions "having dimensions large compared with the distances ...
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308 views

Classical limit of thermal capacity in Debye Solid

In Debye Solid model thermal capacity with constant numer of particles $N$ (canonical ensemble) is $$C_{N}=\frac{9Nk_B}{(\beta \hbar \omega_D)^3 }\int_{0}^{T_D/T} dx \frac{x^4 e^x}{(e^x-1)^2}\tag{1}$$...
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330 views

Relationship between conductivity and electrostatic screening

I'm trying to wrap my head around the concept of electric field screening. Namely I'm trying to reconcile this property of a fluid with the bulk property of conductivity. I can understand how a ...
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Image of spatial distribution of particles in a plasma?

I am looking into the Debye length and to get an intuitive understanding of it I thought I would find an image showing a simulation of the (spatial) distribution of particles in a plasma i.e. a zoomed ...
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418 views

Plasma (quasi)neutrality

There are (in an introductory level) three parameter to consider a plasma to be quasineutral or neutral The time between collisions per oscillation must be greater than one $\omega_p\tau_c >> ...
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279 views

Debye-Hückel theory and the continuum approximation

This question stems from a problem I was doing on the Debye-Hückel theory. It says that the continuum approximation which underlies the Debye-Hückel theory is valid provided that $\lambda_D \gg r_{ij}...
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157 views

Debye Hückel Theory valid for ions?

I am wondering about the following: Is Debye Hückel Theory only used if you look at how an external "strong" field(like a potential by a sphere that has a charge that is 1000times higher than the ...
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Debye Hückel Theory

In the derivation of the Poisson-Boltzmann equation, my textbook arrives at the expression $$ \rho_i = c_+ z_+ F + c_-z_-F = c_+^oz_+^oFe^{-z_+e\phi_i/kT} + c_-^oz_-Fe^{-z_-e\phi_i/kT} $$ where $c_\...
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Why is the conductor an equipotential surface in electrostatics?

Since the electric field inside a conductor is zero that means the potential is constant inside a conductor, which means the "inside" of a conductor is an equal potential region. Why do books also ...
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What is the penetration length of static electric field into conducting metals?

How large is the penetration length for static electric field into good conductors? I have two versions: (1) few atomic spacings $$a\sim n_{e}^{-1/3},$$ and (2) Debye length computed by Fermi ...
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Is solar wind positively charged?

Many times I heared that the solar wind consists of protons and alpha particles. The both are positively charged, but are there electrons in solar wind?
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640 views

Coulomb's law and Plasma [closed]

Does Coulomb's law apply to Plasma?