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.
Questions tagged [debye-length]
26 questions
16
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6 answers
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 conclude, that the surface is at the same potential…
Revo
- 17,504
16
votes
6 answers
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?
Anixx
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1 answer
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 energy $\varepsilon_{F}$ (not the temperature)…
Igor
- 467
5
votes
3 answers
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 understood correctly:
The Debye length needs to be much…
Ofek Gillon
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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 calculated from the Poisson's equation in…
Olexot
- 192
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1 answer
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 of an overall neutral plasma, due to the presence…
maru0032
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Is there any good way to demonstrate Debye plasma shielding in a classroom?
In this age of amazing information exchange, despite loads of glorious YouTube DIY science channels, I haven't seen anyone demonstrate Debye plasma shielding. I can imagine it might be hard to come up with a satisfying demonstration (after all we…
articpenguin
- 55
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0 answers
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 $$\Phi=\frac{q}{4\pi\epsilon_{0}r}\exp\left({\frac{-r}{\lambda_{D}}}\right)$$ and I insert a positive…
NotSoSN
- 207
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1 answer
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 $\lambda_D \gg r_{ij}$ where $\lambda_D$ is the Debye screening…
CAF
- 3,649
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vote
1 answer
Why is the plasma density within a Debye sphere at odds with overall plasma density?
A strongly coupled plasma is characterized by the following attributes:
higher number density
lower particle speeds (lower temperature)
smaller Debye length
continuous electrostatic influence throughout, stronger long range interaction
sparsely…
TrapAlcubierreDrive
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Anisotropic screened Coulomb interaction for particles in a plasma
Background (isotropic screening): Consider a quasi neutral plasma. An ion/electron in a dense plasma attracts opposite-charged particles and repels
those with the same charge, thereby creating a "cloud" around itself. This microscopic cloud shields…
Quillo
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Does Debye shielding occur in non-neutral plasma?
If you have a non-neutral plasma, lets say positive ions, and immerse a negatively charged point source, would that source's field be screened out at large distances? How about if the source was positively charged, would the field be screened out at…
articpenguin
- 55
1
vote
0 answers
Poisson equation with vector as an argument of charge density
I want to solve the Poisson equation with the following charge density:
$$
\rho(\vec{r})=q\delta(\vec{r}-\vec{r_i})-q\frac{1}{4\pi r^2_D}
\frac{e^{-|\vec{r}-\vec{r_i}|/r_D}}{|\vec{r}-\vec{r_i}|}
$$
So I think the first step is to let $\vec{r_i}$ be…
peter mafai
- 451
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vote
1 answer
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 $c_\pm$ is the concentration (of positive or negative…
TMOTTM
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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 between the particles but small compared with the…
