Linked Questions
27 questions linked to/from Why are ions and electrons at different temperatures in a plasma?
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Visualising gas temperature and gas pressure
Gas pressure is created when gas molecules collide with the wall of the container creating a force.
Gas temperature is a measure of how fast the molecules are moving / vibrating.
However, they both ...
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2
answers
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What is meant by "collective behavior" in the definition of plasma?
"Plasmas are many-body systems, with enough mobile charged particles to cause some collective behavior ." [M.S. Murillo and J.C.Weisheit Physics Reports 302, 1-65 (1998)].
In the above definition ...
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2
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2
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535
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How many temperatures has a plasma?
In nonthermal plasma, not all particles move in the same way. The electrons are different from other particles. Both can be described as having a temperature separately. But that would mean, one piece ...
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2
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Why does the electron mean free path need to be larger than the mean interatomic distance?
In an article (over 250 citations) on plasma physics I've read a paragraph which I find very confusing. The authors state that there's a minimum mean free path an electron travels before it is ...
- 562
4
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2
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Differences between "cold" and "collisionless" plasma
I'm just stepping for the first time into plasma physics and I'm studying on Chen's "Introduction to plasma physics" and on the notes of professor Richard Fitzpatrick.
I just seem to not have clear ...
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Limitations of the ideal gas law: When does it fail?
Motivation
I ask this question precisely because I am looking for a fundamental, quantitative explanation of the limitations of the ideal gas law and when it should not be used.
Note, I have found ...
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1
answer
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Ohmic heating in a fusion plasma
In a microscopic classic picture, ohmic heating occurs due to collisions. Let's start with the simplest case: a cooper wire and a battery that induces a current. Electrons start flowing and the energy ...
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1
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1
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How to calculate the free mean path of electrons in the gas mixture? [closed]
How to calculate the free mean path of electrons in the gas mixture? I understand (a little bit) the mean free path concept for the atomic collisions but I am not sure what to do if I am interested in ...
user148787
4
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2
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Why does an oscillating electric field couple more strongly to electrons than to ions?
As stated in Principles of Plasma Discharges and Materials Processing, by M. A. Lieberman and A. J. Lichtenberg, about capacitively coupled plasmas:
(...) the light and heavy charged particles in ...
- 1,046
2
votes
1
answer
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If ions in plasma are not in Maxwell-Boltzmann Distribution, what is the meaning of ion temperature?
From what I understand, if a gas has a temperature $T$ degrees Kelvin, it means that the probability of a gas particle to have energy $E$ is proportional to $\exp(-E/kT)$. It is the physical ...
2
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1
answer
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Significance of the ion Hall parameter
For an ionized Helium gas, for example, MHD Hall generators rely on the mobility ratios between electrons and ions to function and produce a Hall current. As far as I can tell, intuitively, increasing ...
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0
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Why is electron temperature in plasma higher than ion temperature?
Wikipedia states that
The electron temperature of a plasma can be several orders of magnitude higher than the temperature of the neutral species or of the ions. This is a result of two facts. ...
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4
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1
answer
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Temperature anisotropy in plasmas
If a species of a plasma is described by a distribution function $f(\mathbf{r},\mathbf{v},t)$, is it possible to have different temperature (thermal energy) values for different directions (x, y and z)...
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3
votes
1
answer
438
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Pressure in a gas as it becomes a plasma
Let's say you have 1 mole of hydrogen, and you heat it to the point that the H-H bond breaks and you get free hydrogen atoms, and then fully ionized hydrogen ions + electrons.
When H2 becomes 2H (...
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2
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2
answers
354
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What is the PDF of relative collision speeds in an ideal gas?
In the Kinetic theory of gases, the speeds of particles follow a Maxwell-Boltzmann distribution.
However, what if one is interested in the distribution of relative collision speeds, aggregated over ...
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2
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1
answer
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What is a “tenuous plasma”?
This term came up pretty quickly when reading about plasmas, and although it’s somewhat frequent in terms of use, I couldn’t find a clear explanation of what it is, so I figured it’d be useful, both ...
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Wave drag in the interstellar medium
In Earth's atmosphere, an object moving at supersonic or near-supersonic speed experiences wave drag due to the formation of shock waves around the object's leading edge. At high speeds, wave drag is ...
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2
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1
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Mathematical form of distribution function with high energetic beam
Maxwell Boltzmann distribution function (MBDF) has the form
$$f(v)=n(\frac{m}{2\pi k_BT})^{\frac{3}{2}} exp(-\frac{mv^2}{2k_BT})$$ [Basic Space Plasma Physics by Rudolf A. Treumann & Wolfgang ...
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2
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In a plasma, can the ion temperature become larger than the electron temperature?
Let's assume a hydrogen gas, initially at low temperature
The density is low enough so that heating of this gas by inverse bremsstrahlung can be neglected.
Now if a high-intensity radiation source ...
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0
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Is this a valid interpretation of the mean relative speed/collision rate of particles in a Maxwell-Boltzmann distribution?
In textbooks, the collision frequency $Z_{ab}$ between two species "a" and "b" is always given as something like:
$$Z_{ab} = n_an_b\sigma_{ab} \Bigg(\frac{8 k T}{\pi \mu}\Bigg)^{1/...
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1
answer
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Electrons carry the bulk of heat flux in the solar wind?
In the introduction of the attached paper is mentioned that:
Electrons provide additional heating by carrying the bulk of the solar
wind heat flux and through collisions with the protons.
Electron ...
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1
vote
1
answer
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Particle in kinetic gas theory without collision
Hello I have a (Gedankenexperiment) question about the kinetic gas theory. As far as I understand temperature corresponds to kinetic energy. Assume now there would be one particle that does not ...
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0
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How to decompose Plasma ion Drag Force on a particle moving through it?
Almost all papers on plasma mentioned that plasma ions drag on a particle is in the direction is opposite to the velocity of the particle. But no one said anything about the other two components; are ...
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Derivation of the Coulomb Collision Operator for Plasmas
I am attempting to learn about Coulomb collisions in the kinetic theory of plasmas. In doing so, I have come up with an "intuitive" derivation of a Coulomb collision operator. However, the ...
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0
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Ion temperature in plasmas
Normally ions are considered to be at different temperature than other species in plasmas. My question is : How does ion-neutral collision effect ion temperature in a plasma ?
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0
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Is the average collision duration $\propto T^{1/2}/ P^2$?
Question
So I was reading an old question of mine and realized the average collision duration $\langle \tau \rangle $ must be proportional to:
$$ \langle \tau \rangle \propto \frac{T^{1/2}}{P^2}$$
...
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0
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Can you have two different Bohm velocities within a multispecies plasma?
How would you calculate 2 different bohm velocities in a multi species plasma, say H+ and N gas excited by a microwave reactor.
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