Theory, lab and space experiments, and calculations related the physics of [plasmas](https://en.wikipedia.org/wiki/Plasma_(physics)), i.e., matter constituted by [ionized atoms](https://en.wikipedia.org/wiki/Ion).

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Why does AC Conductivty in Drude Theory have an Imaginary and a Real Part?

In the Drude Model the direct current (DC) conductivity is given by the following formula: $$\sigma_0=\frac{ne^2 \tau}{m}$$ where $\tau$ is the relaxation time. Furthermore, the AC conductivity in ...
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55 views

Why in plasma physics usually is given the refractive index of electrons but not for ions?

What is the refraction index of ions in plasma ? And why people do not discuss it in books ? Is it that it is not important for plasma phenomena ?
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181 views

Is there any electric current in a continuous medium of moving charges?

Consider a continuous charged fluid (unlike in real life where charge is carried in discrete chunks like electrons) in a bottle. Suppose that the fluid is stirred in a circular manner and then left to ...
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21 views

What is the refractive index for partially ionized plasma plasma (mixture of electrons ions and atoms)?

I asked a question earlier, why ions are not included in refractive index of plasma . What I do not understand is how a refractive index of plasma can be formed mathematically that is just partially ...
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Simulation of plasma in tokamak

I am reading some papers on numerical algorithms for simulation of plasma in the context of nuclear fusion in a tokamak. I am getting a little lost as there is a huge number of references, and it is ...
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Vlasov equation, Maxwell distribution

I have the Maxwellian distribution: $f(v)=n(\frac{m}{2\pi kT})^{\frac{3}{2}}\exp\left(-\frac{mv^2}{2kT}\right)$ I have to show that it is a solution to the Vlasov equation: $\frac{\partial f}{\...
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66 views

What is the role of plasma in nuclear fusion energy production?

I read that confined plasma in electromagnetic field uses in TOKAMAK nuclear fusion reaction. But I don't know what is the main role of plasma in fusion reaction. Is it use for producing energy ...
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132 views

Fermi velocity $v_F$ and speed of light

Can Fermi velocity $v_F$ be equal to speed of light, $c$, for ultra-relativistic electron plasma waves, in plasma physics, by using Fermi-Dirac distribution function?
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Why did they start Wendelstein 7-X With Helium?

Just saw the first Hydrogen plasma at the Wendelstein reactor. I haven't found anywhere that gives a good explanation as to why they first used a Helium plasma - can anyone shed any light?
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136 views

Using a Plasma Globe to generate real random numbers

I have been thinking how to easily generate real random numbers when I cam across the small USB-powered Plasma globe. My idea would be to place it in front of an light sensor and read the sensor's ...
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1answer
156 views

Difference between fusion plasma and fluorescent lamp plasmas

How is the plasma in a compact fluorescent lamp (CFL) different from a plasma in say ITER or the sun? Why does ITER need 100MK and a CFL can work at practically room temperature (apart from the ...
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894 views

Child-Langmuir space charge law for non-zero cathode potential (non-zero initial electron velocity)

I'm trying to reconcile some conflicting results that I've found in publications that address the idea of the current in a vacuum diode in the case where the cathode has a non-zero potential, in other ...
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207 views

Integrating Factor Solution for Plasma Wave Equation

As part of a derivation in Bernstein '58 [1] a linear first-order (eqn. (9) in the image) appears: But the general solution I would usually take (as appears in Gradshteyn and Ryzhik and checked in ...
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Ionospheric electron density measurements

I've been working on measuring total electron column density (TEC) with multi frequency GPS data. In theory, signal delay caused by TEC differences should affect the code and carrier nearly evenly in ...
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1answer
31 views

How do flames neutralize a static charge?

I was working with a demonstration galvanometer recently when it accidentally picked up a static charge from me lightly rubbing my hand across it. The case was made of a clear plastic. My attempts ...
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1answer
151 views

polarization of a transverse wave travelling in ionosphere with polarization direction perpendicular to earths magnetic field

Assume a transverse electromagnetic wave entering ionosphere such that its Electric field of wave is perpendicular to earths magnetic field. Now, i read that as it will enter plasma, the wave will ...
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20 views

Can a Van de Graaff Generator be used to put plasma at high potential?

Lets say hypothetically, we use a sphere of plasma (ofcourse lab-plasma, stabilized somehow) instead of a sphere of metal in a van de graaff generator. Now can we use it to put a large amount of ...
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Can additional charge be put on plasma?

We all know that plasma is electrically conductive. My question is that is it possible to somehow place more charge on it (lets say like a capacitor) such that it produces its own electric field ...
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273 views

Maxwell-Boltzmann distribution for transport equations

I have to calculate the transport coefficients for the Maxwell-Boltzmann distribution. But I'm not sure what distribution I have to use. As far as I know it should not be the MB distribution for $v$-...
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52 views

Possible Safe Areas In a Solar Flare

Which part of the earth would be the safest in case of the major solar flare? Will it be near equator or something like that?
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Does the solar wind correspond to a net electrical current?

The solar wind is a stream of ions emitted from the sun. Are there more positive than negative charges released? That is, is there any imbalance in the charge emitted from the sun in the solar wind?
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1answer
33 views

What causes a charged particle to follow circular motion in a magnetic field? [duplicate]

I would like to know why particles follow a circular path in a magnetic field, what path they trace and how this path is measured and controlled?
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1answer
633 views

Lorentz force for electrically conducting fluid flow in homogeneous magnetic field

I am mathematician and have paper which models situation when homogeneous magnetic field is applied to moving electrically conducting fluid. There is such Lorentz force formula on which all the work ...
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54 views

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 ...
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Tokamaks and the reason they are still not efficient

I'm curious about why tokamaks are inefficient as generators. In laymans terms, what is the main reason(s) tokamaks still cannot be used as generators? My limited understanding of tokamaks tells me ...
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25 views

The velocity of the charged particle in the magnetic field [duplicate]

Enrico Fermi considered that moving charged particle gains energy in the magnetic field, so its velocity increases. According to the Lorentz Law $\vec F=q\vec v\times\vec B$. Work is $A=\vec F\times\...
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Why doesn't the group velocity of a plasma EM wave equal the phase velocity here?

For plasma EM waves we have the dispersion relation $$\omega^2=\omega_p^2+c^2k^2$$ where the plasma frequency $$\omega_p^2=\frac{n_e e^2}{\epsilon_0 m_e}$$ One can show that $v_p v_g=c^2$, i.e., the ...
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52 views

Can conducting electrons in a metal be modeled at all as classical particles?

I have seen computational models that treat the highest energy electrons in a conducting metal as classical particles in a plasma, the ions being held in place with some sort of heuristic nearest-...
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86 views

What is the difference between metallic hydrogen and plasma of hydrogen?

As far as I know, metallic hydrogen and plasma seems share some common properties, eg:conduct electricity, nuclei share electrons, high temperatures... So my question is, is metallic hydrogen in fact ...
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785 views

Do stars remain electrically neutral? [duplicate]

How electrically neutral do stars remain through their lifetime? As an example, I could imagine processes such as coronal mass ejections leaving the Sun in a slightly charged state. Are there such ...
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23 views

Project Orion pusher plate computer modeling

Linked from the space.stackexchange forum: http://space.stackexchange.com/questions/15051/orion-project-npp-pusher-plate-computer-models-and-survivability Project Orion is discussed as if it is a ...
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73 views

A question about the Fermi acceleration

In high school physics, we know that a charged particle cannot gain energy from a magnetic field. But, it seems that in the so-called Fermi acceleration, the particle is accelerated by the magnetic ...
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GEN3's 10nm-30nm Contiuum Radiation Measurements

What is the most likely explanation for the 10nm-30nm continuum radiation reported in "Validation of the Observation of Soft X-ray Continuum Radiation from Low-Energy Pinch Discharges in the Presence ...
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83 views

Potential energy of a spherically symmetric charge density in a spherically symmetric electrostatic potential

I'm interested in calculating the potential energy of a spherically symmetric charge density in a spherically symmetric electrostatic potential. More specific, I'm currently trying to calculate the ...
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1answer
41 views

Does nuclear fusion of light nuclei occur in fire or boiling water?

At the temperature range of ordinary fire or maybe even ordinary boiling water, is the Coulomb potential between light atomic nuclei occasionally overcome to give way to fusion? Basically, how are ...
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71 views

Units in Plasma Physics

What are the units people use in plasma physics? I am having hard time converting an equation from an old paper to SI units. I saw temperature being defined in $eV$. I assume this is $eV/k_B$ with $...
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Plasma Seperation Technique

Is it possible to break a gas sample in ions and separate those ions and store in two different tubes? If there is an experiment and formula related to it then please mention that too.
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Is the permeability of plasma equal to the permeability of free space?

I learned that in Maxwell equations for plasma, the permeability is equal to the permeability of free space so that means the relative permeability is equal to the unit tensor. Also we have always ...
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1answer
68 views

What causes polarization current density in plasma?

Plasma current density is defined as $\textbf{j}=-\mathrm{e}n_e\textbf{u}_e$ where $\mathrm{e}$ is electron charge, $n_e$ is electron concentration and $\textbf{u}_e$ is electron velocity. What ...
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26 views

Polarization current introduced by induced charge?

Should we count the current density that introduced by the movement of induced charge as free current or magnetized current or neither? And why?
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Ion Source Design

I want to design a DC arc discharge ion source but I can't find a good book that explains how to do it. Can anyone please recommend me a book or paper that explains this? thanks
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Schwinger metals?

Consider an electromagnetic field that does reach values above the Schwinger limit inside a region of space $R$, on each oscillation. Once the field exceeds the Schwinger intensity, the field causes ...
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9k views

Can plasma turn back into gas, solid, or liquid?

I wanted to know if, since basic chemistry teaches you that states of matter can be changed, I was wondering particularly about plasma. I know that virtually all of the Sun is plasma, so I was ...
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Physics 3 recommended book with solutions [duplicate]

I'm new to this forum and wanted to ask for a recommendation for a book which has these subjects with problems and solutions:(if this is not a valid question please tell me) -Intro to Waves -Fourier ...
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249 views

Does matter found at densities of white dwarfs “feel” more like a solid, liquid or gas?

I'm wondering what it would be like to touch or interact with very dense degenerate matter like this found at white dwarfs. I understand that white dwarfs are initially very hot, but for the sake of ...
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Is green superheated plasma possible?

I've noticed that video games like Fallout 4 depict the plasma fired from plasma weapons as green. Is there a way hot plasma can look green in real life? I know some gases emit green light when ...
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1answer
41 views

Recombination rate/time calculation for plasma vs. solid state semiconductors

I've been able to find how to calculate the recombination rate for semiconductors as a function of the type of semiconductor (like silicon), the doping material, the concentration of the excess ...
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1answer
71 views

What phenomena occur in a low voltage arc between copper and graphite electrodes, and why is the result dependent on electrode polarity?

I was playing around with a laboratory power supply, drawing arcs between electrodes of various materials. I noticed phenomena that I found interesting, and couldn't really explain myself: The ...
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66 views

Do plasmas have their own magnetic fields?

Do Plasma generate a magnetic field of their own ? Can they cause electromagnetic induction?? For example if a hydrogen plasma is ionized and its electrons removed.. And the protons accelerated ...
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91 views

What makes Jacob's ladder spark to go upwards?

In a Jacob's ladder (https://www.youtube.com/watch?v=GaC4BnbH1NY&index=3&list=PL_SAbPKia2YMFi-t8z5WFYCd86Plcs1Un) a spark is originated in the bottom and climbs up to the top. I have read in ...