Theory, experiments and calculations related the physics of plasmas, i.e., matter constituted by ionized atoms.

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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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Kittel solid state physics handbook - Plasma oscillation of a ball - Am I solving this right?

I'm self learning nanotechnology undergraduate and I'm trying to solve a problem from chapter "plasmons, polaritons and polarons". This is it: Frequency of uniform mode of plasmons in a ball is ...
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Why is there not much research into nuclear physics with plasmas?

There is a lot of research and theory around fusion reactions with plasma, but is there a reason why plasmas cannot be used for researching other nuclear reactions, either in the lab or from ...
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What does a sample of the Sun look like? Does it look like fire or gas?

Suppose that in the future a highly resistant spacecraft went to the Sun and collected three samples of the Sun: one from its surface, one from its core, and one midway. The three samples were put ...
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spectrum of discharge of air

Where do the various colors in electrical discharge of air with a high voltage originate from? Are these transitions in ionized nitrogen gas or unionized gas? Are chemical reactions involved? I assume ...
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Magnetic fields in plasma at equilibrium

I'm wondering if it is possible to have a plasma reach an equilibrium state where no more entropy is produced but it still has frozen-in magnetic field lines. The problem is the field lines have a ...
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Calculate the potential induced by beam

This exercise is from Plasma Physics and Fusion Energy by Freidberg. A cylindrical conducting vacuum chamber of radius $r=a$ is filled with a uniform plasma of density $n_0$ and temperature ...
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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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Radio wave propagation in ionosphere

Radio communication is based on the concept that a radio signal incident on the ionosphere is reflected if the frequency of the wave matches the plasma frequency. But what exactly happens? Is it ...
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Boltzmann factor predicts arbitrarily large numbers of electrons at high potential?

In deriving the Debye shielding length we are told that the Boltzmann factor for particles of charge $q$ is: $n_{q}=n_{0}\exp(-q\phi/kT)$ If we assume the potential $\phi$ is positive, then the ...
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64 views

Why is quasineutrality required for a gas to turn into a plasma?

Why is quasineutrality a required condition for a plasma to exist? Quasineutrality means that no density of electrons and ions should almost be equal but not exactly equal. Can anybody explain this ...
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why ions and electrons are at different temperatures in plasma?

In plasma, collision rate among ions or electrons is much larger than the collision rate between ions and electrons. why is that so?
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Fusion plasma compression with liquid metal

General Fusion plans to use an imploding shockwave of molten lead to compress a magnetized plasma "spheromak" target in order to make it burn more efficiently. How come the lead does not quench the ...
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Fusion reactors why does size matter?

I've been following articles about fusion recently, and with the ITER project mostly. I have noticed that their view point is they need to build a large scale reactor in order to achieve their goals. ...
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399 views

Difference between irreversible and entropy?

Cedric Villani recently wrote an article on Landau damping, where at least one topic discussed confused me. Besides discussing the issue of how a process can be microscopically reversible and ...
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Relationship between plasma physics and quark gluon plasma

To what extent do the ideas common in modern plasma physics, such as magnetohydrodynamics, cold plasma models, common types of plasma waves, Maxwell's Equations, etc, relate to the study of quark ...
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Particle acceleration at magnetized shocks by convective electric fields?

Let us assume we have a flow of charged particles in a quasi-neutral state (i.e., a plasma) convecting at some speed, $\mathbf{V}_{sw}$ = V$_{sw}$ $\hat{x}$, and the particles have species-dependent ...
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Is a plasma necessarily made of monoatomic ions?

Is it possible to have a plasma made of polyatomic ions instead of monoatomic ions? I want to know all the details why such a thing may be attainable or not and, if possible, what methods we can use ...
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Aftermath of Plasma Arc

You have a chamber with constant amount of gas (say either helium or argon). You create the plasma with an arc and turn it off. How much of the gas used to create the plasma returns back to helium or ...
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What happens when a slow wave reaches lower hybrid resonance?

Lower hybrid resonance occurs when $n_{\perp}^2$ goes to infinity, and it occurs only for the slow wave solution, not the fast wave. Since $n_{\perp}$ is proportional to $k_{\perp}$, and $k = \frac{2 ...
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Physical reason for magnetic mirroring?

I understand the mathematical derivation of magnetic mirroring, which usually starts from the conservation of the magnetic dipole moment (e.g. in a plasma). But physically: a mirrored particle is ...
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Why does the majority of smoke leave when flames appear?

When I burn wood, paper, or other plant matter, where there is a flame, there generally isn't too much smoke, but it I blow the fire out, smoke starts billowing up. It billows thicker and thicker as ...
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What materials are used in non thermal plasma?

While reading about non-thermal plasmas, I came across their ionization potentials(~1%), and other capabilities, such as their non Maxwellian energy distributions. At what temperatures, and pressures ...
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Formula for Electrical Arc Length

I was playing with some High-Voltage the other day, when a question popped into my head. Can you calculate length of an electrical arc? It probably would be proportional to :- 1. Voltage of the source ...
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Is the plasma state always visible?

All the examples of plasma I have come across are visible. Is there any plasma which is not visible? For example, during a dark lightening we don't see the radiation because its gamma radiation. Is ...
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Why do we deal only with large scale magnetic fields in astrophysics, and not electric fields?

In astrophysics there is a lot going on about strong, large scale magnetic fields: in stars (prominences), magnetic dynamos, compact accretors collimating jets, etc. There's even a special ...
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Are Mach Diamonds radially symmetrical?

Videos like this show a form that suggests a radial symmetry in the gas jet. The same is reinforced by schematic illustrations. But other images, like this, look like there is a twisting structure ...
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Is it true that gravitational lensing only occurs for objects made of plasma?

The question concerns this video: It says that the Gravitational Lens effect is an illusion, meaning it's not caused by gravity but by change in density of a plasma atmosphere. It claims further ...
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How do I modify a 3-D simulation grid to be 2-D?

I am creating a particle in cell simulation that models an electron plasma in a cylindrical container. Part of this process is assigning charge density to grid points based on the position of each ...
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Poynting Vector between Capacitor - With electrons in between!

Consider a capacitor with voltage $V = V_0 cos(\omega t)$, radius $a$ and separation $d$. Electrons are distributed uniformly with number density $n$. I want to find the poynting vector between the ...
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Plasma Question: Expression for electron temperature in terms of the voltage of each prong of a triple Langmuir probe?

So I am trying to derive an expression for electron temperature based on the voltages on a triple Langmuir probe. I have pretty much been following the triple Langmuir probe derivation on wikipedia ...
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Absorption of waves in a plasma

Suppose a plasma has characteristic frequency $\omega_p$. Since $$n = \sqrt{\left(1-\frac{\omega_p^2}{\omega^2}\right)} $$ For $\omega<\omega_p$, the refractive index will be imaginary - which ...
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183 views

What's the relationship between glow and arc discharge?

I'm trying to understand the differences between an arc and glow discharge. Most texts I have found on the Internet only describes the observed differences but doesn't really explain what happens on ...
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78 views

How a plasma reacts with an AC electromagnet

Any metal conductor such as aluminium or copper is a conductor because of the free electrons in such metals. Plasma also has free electrons so I would like to know if you can repel plasma the same ...
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plasma pressure initial condition

The authors in the paper below did a simulation of plasma plume evolution from a laser heated metal target. They used compressible transport equations and ideal gas EOS for Ar. I am having difficulty ...
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How hot can plasma get?

I remember reading about an experiment where fine rods of tungsten were super-heated with millions of amps of electricity, melting them into ionised gas and were then compressed (by magnetic fields?) ...
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Magnetic hot air balloon [duplicate]

Normally, hot air balloons are limited to 60,000 ft (related question), the limits being the mass of the physical structure containing the air, and the heat source. If one constructed a magnetic ...
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Dielectric Tensor vs. Conductivity Tensor in (Cold) Plasmas

I'm studying Waves in Cold plasmas right now, but I guess my question is generalizable. It's about the 4th Maxwell Equation in polarizable / conductive media: $\nabla \times H = \frac{1}{c} ...
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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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How do you integrate an expression over a variable in the limit of an integral?

I am trying to follow the steps to solve the integro-differential equation that arises from a plasma sheath problem given in this paper. This is the step I can't follow: ...
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How can a star emit light if it is in Plasma state?

I understand that star is in Plasma state (all nucleus and electrons are not bound to each other and moving around freely) Photon is emitted when an excited electron moves back to lower orbit. So 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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Conserved quantities and total derivatives?

I am having a bit of a crisis in understanding of the physical meanings of total derivatives. When a quantity $\rho$ (be it a vector or a scalar) is said to be conserved, then (mathematically) ...
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Simulating electrical sublimation of aluminium foil

When i apply high voltage (through a capacitor bank) across an aluminium foil, it gets converted into plasma. I want to simulate this process and study the properties of the plasma produced ...
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Camp Fire Crackle

I was sitting around the camp fire and there was a periodic sound of cracking and pieces of the burning wood flew off. My question is what is the mechanism for the cracking of the wood? I was thinking ...
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Radiofrequency attenuation in cold plasma

The missile plume can be considered a cold plasma. If a radio signal passes across the plume it's attenuated. Obviously the attenuation depends on the frequency of the signal. Where can I find some ...
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metastable energy levels

can someone give me a good definition of "metastable energy levels" in a helium plasma (glow discharge). Am I right when I say : "by adding some neon in my helium plasma, I will obtain a molecular ...
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Why do noble gases stabilize plasma discharges?

In the plasma literature, noble gases—usually helium or argon—are frequently said to 'stabilize' plasmas. For instance in this patent, the inventor states that the plasma can be stabilized "by adding ...
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What happens to the electrons that escape an atom when matter is converted to a plasma state?

Lets say we have a device that generates plasma fields; if this device creates plasma by heating a gas, where do the electrons that escaped the "orbits" of the atom go? Would the electron physically ...
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What will happen if we will be able to produce a quark-gluon plasma and the we cool it down?

Lets assume that we can produce a quark-gluon plasma and then we try to cool it down, what will happen to it ?