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

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Fusion - A List of Experimentally Achieved Beta Numbers in Magnetic Confinement [closed]

I want a list of all the beta numbers achieved in across all magnetic fusion energy devices. This is not theory, but the actual number measured experimentally. No list like this exists. The beta ...
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Magnetic Energy Density Equations

I have a plasma with a magnetic field through it and I want to know the magnetic energy within the plasma. I have the simple equation U=(B^2)/mu for the energy density. But my question is then, if ...
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Gravitoelectromagnetism higher-order effects

See http://en.wikipedia.org/wiki/Gravitoelectromagnetism#Higher-order_effects According to the Higher-order effects... "Gravitomagnetic arguments also predict that a flexible or fluid toroidal mass ...
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Liouville's Theorem and Boltzmann equation for plasma

The Boltzmann equation for a plasma can be thought of as coming from a continuity equation in the 6 dimensional phase space of the plasma with coordinates $\left\{x,y,z,v_x,v_y,v_z \right\}$. So ...
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What causes the electrical reaction between two carbon rods touching?

I recently watched this video in which carbon rods from a 6V lantern battery are removed and then touched together to create a makeshift arc reactor furnace. This produces electrified plasma which can ...
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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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574 views

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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Calculating the magnetic permeability of a known plasma

I have a plasma, of which I know the composition, temperature, exact electron/ion/particle densities. How can I then calculate a theoretical permeability of the plasma. Is this even possible? I ...
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402 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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Does plasma has any chemical formula?

As far as I understand, plasma is another stage of matter like solid, liquid or gas. All of these have chemical formulas, however does plasma has chemical formula as well? If it doesn't, what's made ...
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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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Why does a non-contact voltage detector light up when you touch a plasma ball with the other hand?

I am doing a science experiment and we decided to try holding a non-contact voltage detector up to plasma ball. We were surprised that it would light up when it was 3 ft away from the plasma ball. I ...
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86 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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41 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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Can Gases conduct Electricity?

Liquid electrolytes ionize and hence a current can pass through them. So if a gas can ionize, can it conduct electricity too? If so, what are a few such gases?
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Woltjer's Theorem, partial or total derivative?

Morning everyone.. I am currently studying Plasma Physics on a recent book named "Basics of Plasma Astrophysics" by Claudio Chiuderi and Marco Velli. While demonstrating Woltjer's Theorem they state ...
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$E \times B$ drift plasma physics

Do you need to have an electric field in order to have an $\mathbf E \times \mathbf B$ drift? I'm confused because it's seems that there is an induced E-field from the charge separation due to forces ...
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170 views

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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Harvesting hydrogen from a star

I've been thinking about what highly technologically advanced civilisations would do once their energy requirements become comparable to the total output of a star, and how such activity could be ...
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1k views

Is there a phase transition between a gas and plasma?

Does a phase transition occur as a gas is heated to create a plasma? If so, is this a first or second order phase transition? Also, does the presence of a phase transition depend on the pressure or ...
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Dense plasma focus properties

Any Dense plasma focus scientists here? Could you explain the effects of having the anode: with less number of rods? hollow/non-hollow?
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MHD stability - boundary conditions

In Freidberg's 'Plasma Physics and Fusion Energy,' ch. 12.4 p 311, right after deriving the Linear Force operator and momentum equation in which it is used $$ -\rho \omega^2 \boldsymbol\xi = ...
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Particle-in-cell (PIC) code Virtual Laser Plasma Lab (VLPL)

I am writing a simulation code to model betatron X rays produced by electrons accelerated using laser wakefield acceleration (LWFA). I have heard about 3D PIC (Particle-in-Cell) code VLPL (Virtual ...
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79 views

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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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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Plasma frequency

I have a neutral plasma and I need to solve Maxwell equations given the charge and current densities on the plasma. In order to do it I need to know the electrical permittivity $\varepsilon$, I've ...
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48 views

Inert Gases in Plasma Balls

Recently I have been reading about the fourth state of matter, viz.Plasma. Everywhere I read that plasma is formed when Gases are given enough energy and they lose their electrons to form a "cloud" of ...
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What are non-Abelian plasmas?

I know what a non-Abelian group is: a group whose operation does not obey commutativity. Does this have anything to do with a non-Abelian plasma? I'm not really looking at a specific paper, but I'll ...
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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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Electrostatic ion thruster neutralizers

All electrostatic Ion thrusters have a neutralizer electron beam, but why are they required? Is avoiding the accumulation of negative charge the only reason? I would've thought that the main reason ...
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112 views

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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47 views

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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78 views

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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25 views

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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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 do many books say quasineutrality is needed for a plasma to exist?

Many books on plasma physics (Chen, Goldston, Lieberman) say that quasineutrality must be satisfied for the matter in question to be a plasma. Yet, we know that non-neutral plasmas exist. So why do so ...
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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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Why does only one side of a neon lamp glow?

When applying DC to a neon lamp, only the negatively-charged electrode glows: The voltages across the lamps are left: DC (left lead positive), middle: DC (right lead positive), and right: AC. ...
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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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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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Why is lightning considered a plasma?

I was wondering why a lightning bolt is coined as "plasma", or a "spark" from an electrical wire/device is as well, yet flares, molten lava, and burning buildings are not(flares are pyrotechnic, ...
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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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Why were space physicists wrong about the location of the heliopause?

The heliopause is now estimated to be something around 100 AU (1 AU = Astronomical unit = about the earth sun distance). See the wikipedia article: http://en.wikipedia.org/wiki/Heliosphere From ...
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plasma frequency in non-neutral plasma

Is it possible to see the oscillations with plasma frequency in a gas of particles of the same charge (not mixture of positive and negative charges)?
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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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Jupiter radiation belt: where >MeV particles comes from?

When I read some discussion about exploration of Jupiter moons, or possibility of life there, a common argument is high dose of radiation in Jupiter's radiation belt (several orders of magnitude ...
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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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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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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 ...