Questions tagged [plasma-physics]
Theory, lab and space experiments, and calculations related the physics of plasmas, i.e., matter constituted by ionized atoms.
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Dispersion Relations in a Cold, Unmagnetized, Collision-less Plasma
Currently I am trying to understand the physics of waves in cold plasmas. So in a cold, collison-less, unmagnetized plasma you can derive two different different dispersion relations: one for ...
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How to create a spectral image from a gas?
Let's say I want to put air through an optical spectrometer. It doesn't need to be NASA accurate, but suppose I just want a rudimentary measure of carbon from the carbon frequencies.
How can I get &...
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Does an electric arc formed in air create more heat than in neon or argon?
When you create an arc in the air it becomes several thousand degrees and is hot enough to weld with.
However, plasma arcs in neon/argon are cool to the touch, and are used for neon lighting and small ...
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Conservation of Magnetic Flux and vorticity in astrophysical plasmas
I have a doubt about the conservation of magnetic flux in astrophysical plasmas, in particular in the presence of turbulent motions and vorticity (surely due to poor understanding of vector identities)...
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How can the magnetic mirror force act along B direction if it is derived from $q\vec{v} \times \vec{B}$ force?
A typical derivation of the magnetic mirror force of a charged particle in a magnetic field such as from Nicholson (1983) pg 26 uses the $q \vec{v} \times \vec{B}$ force, conservation of the dipole ...
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Why do some nuclear tests feature what seems to be an additional fireball on top?
Have a look at this frame from footage recorded during Operation Hardtack I - Test POPLAR
Clearly the bit on top is extra hot, and it seems to be above the main fireball, or at least not part of the ...
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Potential Perturbation of the Ionosphere by Artificial Re-entry Plasma Dust
Recently I read on Spaceweather.com
https://spaceweatherarchive.com/2024/02/
a surprising paper according to which the space debris or vaporized material (mostly metals) that has been deposited in ...
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Definition of injection spectrum of an electron beam
Referring to Plasma Astrophysics, Part 1, Eq 4.32,
The number density of electrons in the beam at a distance $z$ from the injection plane at $z = 0$ is defined as,
$$
n_b(z) = \int_{0}^{\infty} \int_{...
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How can I determine sound speed of ions in plasma sheath
Since the definition of sound speed, ($c_{s}$), in each ion s$th$ species ($is$) expressed that:
\begin{align*}
c_{s,is} = \sqrt{\frac{k(T_{e}+T_{is})}{m_{is}}}.
\end{align*}
How can we determine ...
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Dimensionless non-relativistic energy of fast particles
In Plasma Astrophysics, Part 1, Equation (4.7)
the dimensionless non-relativistic energy of fast particles ($m$) in a plasma with electrons ($m_e$) and protons ($m_p$) is defined as,
$$
x = \frac{m v^...
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Derivation of kinetic equation for fast particles in a plasma
Referring to Plasma Astrophysics, Part 1, author: Boris V Somov, 4.1.1,
We have the kinetic equation with Landau collisional integral,
$$
\frac{\partial f}{\partial t} + v_{\alpha} \frac{\partial f}{\...
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Is there a ponderomotive force due to a traveling wave?
Imagine a traveling, EM wave passing through some plasma. The waveform is given by the vector potential:
$A = (0, -\frac{cE_0}{\omega_0}\cos\eta, 0)$
where $\eta = \omega_0t-k_0x$ is the phase. From ...
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Dynamic of Alfvén waves in a hot magnetized plasma
I'm trying to derive the dispersion relation of Alfvén waves (AW) by solving analytically the Vlasov-Maxwell equations for a magnetized hot plasma but I'm confused. A simple question, to treat AW ...
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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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Muon-catalyzed fusion: muon number
I recently read a paper "Meson-catalyzed fusion in ultradense plasmas" (it is behind a paywall: only subscribers to Physical Reviews E can read it) that claims that muon-catalyzed fusion in ...
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Validity of equation for $E \times B$ drift in SI and Gaussian unit systems
I derive $E \times B$ drift $\vec v_{E \times B} = \dfrac{\vec E \times \vec B}{B^2}$ and in SI I use V/m and T for the fields. I do not use Gaussian (cgs) units often, but I thought this equation ...
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How to convert from momentum to energy distribution? (relativistic electrons)
I am using a gyro-kinetic simulation tool 2103.16457 which solves the 3D Fokker-Planck equation for the electron population in tokamak plasmas and evolves plasma parameters self-consistently. In many ...
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Can plasma be made dense enough to the point of acting like a solid without reaching extreme temperatures. Such as a cold plasma behaving in this way
Could a cold plasma be densified until its particles are so densely packed together that it behaves like a solid without reaching extreme temperatures? If so how?
Edit: okay there seems to be a ...
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Magnetic mirror and pitch angle of plasmas
I've been learning about magnetic mirrors and how the pitch angle determines whether a particle will be trapped in it or not. I've also learnt about how, when a plasma is trapped, collisions between ...
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Removing surface contamination from Langmuir probe during glow discharge in residual atmospheric gases
I am writing this question to ascertain if it is possible to clean a Langmuir probe by biasing the probe negatively or positively with respect the plasma potential, during a glow discharge with oxygen ...
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How powerful of a continuous wave laser do you need to create a laser induced plasma channel
I have been researching electro lasers. However I keep on finding resources of pulsed electro lasers however I have not found any resources on continuous wave electro lasers. So could continuous wave ...
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Looking for a book of which I have one chapter about plasmons
I am looking for a book of which I have one chapter. I tried to find this book by references and by copying the text in the GPT chat however without success.
One chapter was sent to me by a professor ...
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Broad and narrow line regions of active galaxies: is the matter orbiting a massive black hole in the state of plasma?
The broad and narrow line regions (BLR and NLR) of an active galactic nucleus (AGN) are commonly described as regions of gas emitting atomic spectral lines whose width is broadened - via the Doppler ...
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What is the balanced nuclear fusion equation?
Given that the deuterium-tritium (DT) reaction has been identified as the most efficient for fusion devices, what is the ultimate balanced nuclear fusion equation?
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Magnetohydrodynamic Walens Equation [closed]
How to derive Walens Equation from Continuity Equation and Induction Equation.
Continuity Equation:
$\frac{d \rho}{dt} + \rho \nabla.v + v.\nabla\rho=0$
Induction Equation:
$\frac{dB}{dt}= -B(\nabla.v)...
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How to practically generate longitudinal waves in a plasma
It can be read almost everywhere that plasma is the best convertor of transverse waves to longitudinal waves.
I'm not much interested in the theory here. Rather, I would like to know how to do it in a ...
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Linearization of momentum equation of MHD equations
The momentum equation of the MHD equations is as follows
$$\rho \left(\frac{\partial \mathbf{v}}{\partial t} + (\mathbf{v} \cdot \nabla) \mathbf{v}\right) = -\nabla p + \frac{1}{\mu_0} (\nabla \times \...
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Fourier Transform the Total Interaction Energy for a Coulomb System
It seems that many Posts have solved the Fourier transform of the Coulomb interaction $V(r)=1/r$ which is $v(k) = 4\pi / k^2$. This is not my question.
I have come across the Fourier transform (Hansen ...
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Ideal ignition temperature for a D-T plasma fusion reaction
I've been trying to calculate the ideal ignition temperature for a 50-50% Deuterium-Tritium (D-T) reaction. In the literature this value is $4.4$keV and I'm getting $5.2$keV. Here's how I'm carrying ...
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How cold can cold plasma get?
I have been researching cold plasma for a project. I am trying to write a diagram on the temperatures of cold plasma but I can’t find any good resources on the temperature range of the plasma. So my ...
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Should we expect lightning-like phenomena as matter enters the accretion disk of a black hole?
As matter enters the accretion disk it will rapidly turn into superheated plasma. I would expect this to coincide with lightning-like phenomena due to the electric potential difference between this ...
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Mathematical modeling of low-temp plasma
I am working on a heavily mathematically project about plasma. In particular, I want to find references that treat the problem from microscopic models that include relativistic and magnetic effects (...
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Would an ionized accretion disk experience radial charge separation?
(Sorry if I'm using the wrong terms, but I've yet to find any search terms that seem related to what I'm thinking of. If I did know what to search for, I wouldn't be asking this question.)
Would an ...
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What's physical meaning of 2-point correlation function in holographic condensed matter?
Background: In AdS/CFT, we can do calculations in AdS spacetime, and get the result in CFT. When we consider RN-AdS black hole/brane, 2-point correlation functions in CFT can be obtained, which are ...
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Integral expression for the wave vector in Landau's collision integral
I am trying to understand a derivation presented in a lecture note on plasma physics (Landau's collision integral) regarding the wave vector $\mathbf{k}$:
$$ \int \frac{d\mathbf{k}}{(2\pi)^{3}}\frac{\...
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How would I account for non-linear refractive index effects in a nitrogen based medium?
I am trying to estimate the clamped intensity of a 90 fs femtosecond laser when it passes through a flow of nitrogen that is exiting a nozzle. Prior to the nozzle, the incoming nitrogen flow is heated ...
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Magnetic Field of Earth and Turbulence of plasma
We generally know that plasma turbulence creates magnetic field (here, I have assumed that it happens through the dynamo effect). it is also affected by magnetic fields. Is it possible that plasma ...
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Electron Orbit at the Null Point (DC sputter coating)
This situation pertains to 'thin film sputter coating.'
Suppose I have some magnets in between a high voltage anode and cathode in a suitable vacuum. I understand that the electrons get trapped in the ...
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Electron impact ionization
I am looking to study more about electron impact ionization. I noticed that this topic or anything collision-related, is not present in Chen in detail. Is there another resource that I can use to ...
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Linearzing technique for the Vlasov equation
I am currently reading a paper on a quantum algorithm to solve the linear Vlasov equation with collisions (https://doi.org/10.1103/PhysRevA.107.062412, A. Ameri, E. Ye, P. Cappellaro, H. Krovi, N. ...
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What does non-local transport mean in plasmas physics?
I found a lot of plasma physics works that talks about non-local transport, what is non-local transport in plasmas? What does non-local transport mean ? Some examples please.
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What is the verb for plasma formation?
Simple question: what is the verb for the phase change from gas (or any other "regular" state of matter) to plasma? The best thing I can think of is "ionization into a plasma" but ...
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Why is the electric field time independent in the induction equation of the magnetohydrodynamics?
Why does the induction equation of the magnetohydrodynamics assume the electric field $E$ is time $t$ independent or $\frac{\partial E}{\partial t}=0$?
Note: I am querying about the general case ...
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In a tokamak, is there a density-dependent limit on plasma current?
In a tokamak, the kink limit places an upper bound on the magnitude of the plasma current. For example, Parisi and Ball (2019) write this limit as (p. 246)
$$I\lesssim\frac{1}{q}\frac{2\pi}{\mu_0}\...
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How to deduce the 2d Fermi integral with drift velocity?
I read the article https://arxiv.org/abs/2106.01296, and i see in the eq. (3) an expression for the local electron density using a 2D Dirac distribution with drift velocity,
$$f_{\alpha 0} (r,p,t) = \...
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What is the typical range of the percentage of energy conversion in magnetic reconnection?
I want to determine a suitable range for the efficiency energy conversion of magnetic energy to thermal energy in usual magnetic reconnection because usually it is said that this process is highly ...
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MHD plasma regime clarification
Could you give an intuition about why does MHD requires the following condition in time and spatial scales, please? Thanks.
At scales much larger than the mean free path and gyroradius, and time ...
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What is this anode discolouration in plasma tube?
I made a argon plasma tube with 954 bronze aluminum bronze electrodes. After running for some time the anode (left) face is a silver colour. The cathode is on the right.
Does anyone know what this is? ...
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Statistical mechanics of a mixture that can form clusters
I am not sure how to look for references for the following problem. Imagine having a collection of 2 kinds of particles of density $n_1$ and $n_2$ that can arrange themselves in "clusters" (...
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Magnetic reconnection in MHD theory [closed]
What does the MHD theory predict when two regions with magnetic field of opposed polarization interact? When we take in account the resistivity then we can observe a rearrangement of the topology due ...