Questions tagged [plasma-physics]
Theory, lab and space experiments, and calculations related the physics of plasmas, i.e., matter constituted by ionized atoms.
614
questions
-1
votes
0answers
14 views
Can plasma be cooled without turning back into a gas, liquid or solid
I’m trying to construct a theory on if the plasma sword in the halo universe would be possible in the real world.
So basically what the plasma sword is it is plasma sculpted into a sword shape by a ...
1
vote
0answers
31 views
Why do tokamaks have so few toroidal field magnets?
From the ITER webpage itself, the tokamak has only eighteen toroidal field magnets. If the magnetic field is directly and linearly dependant on the number of coils around the torus, then why did the ...
-1
votes
0answers
24 views
What shapes could we theoretically make a plasma window? [on hold]
I have been reading up on the plasma window, originally discovered by Ady Hershcovitch. A copy of his original paper can be found here. Essentially it has been shown that plasma arcs can be used to ...
0
votes
1answer
22 views
Boltzmann distribution of electrons at thermal equilibrium in a plasma
In Chen's Introduction to Plasma Physics and Controlled Fusion, it says the following during the discussion of Debye shielding:
However the last equation tells me that the electron density $n_e$ will ...
0
votes
0answers
22 views
Plasma Flow Direction
How can plasma flow be directed? I’m having a hard time figuring it out this could be done considering the opposing polarities of the ions and the electrons.
0
votes
0answers
12 views
Breakdown Strength of Semiconductors & Metals [closed]
What order of magnitude is the electrical breakdown strength of pure metals as well as metal oxides?
By electric breakdown strength I am referring to the field strength at which you obtain a single ...
0
votes
0answers
20 views
One Atmosphere Uniform Glow Discharge
One Atmosphere Uniform Glow Discharge Plasmas are created by simple apparatus and well known high voltage electronic circuits. The electronically generated plasma is sometimes used to disinfect ...
1
vote
2answers
42 views
How can increasing the speed and/or mass of a particle reduce, not increase, it's frequency?
In a Physics World article called 'Neutrons on a Lab Bench', from 30 January 2013, it says,
'...Yin and Albright calculated that a very intense laser beam should be able to boost the speed of ...
-1
votes
0answers
47 views
How does the strong force work in plasma?
For a very long time I have thought of inter-elemental conversion, like lead to gold, or just separating the components of one element to create another. From my understanding, you could overpower the ...
0
votes
1answer
33 views
Plasma From Metals
Is it possible to create a dense gaseous plasma from Metals like aluminium, iron etc... using things like Z Pinches? If yes, what would be the efficiency of the process?
In a cylindrical array Z ...
0
votes
0answers
17 views
$H_2O$ dissociation by ionization in a discharge tube
As a casual amateur scientist, I wonder if it is efficient to electrolyse water in a discharge tube. I imagine that there would be 4 electrodes arranged perpendicularly. the first set of electrodes ...
6
votes
1answer
49 views
What causes the vertical bands of light in an aurora?
I was lucky enough to witness a medium-strength aurora recently in Iceland (KP ~3). We saw the classic rippling arc of green light, which at times seemed to consist of smaller flickering vertical ...
2
votes
1answer
67 views
Superman threw a net with a lot of nukes into the Sun. What happens now? [on hold]
The iconic scene in "Superman IV: The quest for peace" shows the eponymous character throwing a net filled with nuclear missles into the Sun.
If that were to happen in real life, what would happen as ...
2
votes
1answer
35 views
Why is a spatial grid necessary in plasma simulations?
I am new to the topic and I am reading Plasma Physics via Computer Simulations by Birdsall and Langdon. The authors claim that working with a spatial grid is more efficient opposed to considering the $...
0
votes
1answer
24 views
Can a Tokamak-Based Mainframe feed Plasma to larger pipe-structure in order to create plasma-based propulsion engines?
Can a Tokamak-Based Mainframe feed Plasma to larger pipe-like structures in order to create plasma-based propulsion engines?
It is a rather naive question.
0
votes
0answers
14 views
How to derive the induction equation for Spatial varying conductivity?
How to derive the induction equation from Maxwell equations (without displacement current) and Ohm’s law for Spatial varying conductivity?
0
votes
0answers
18 views
Ambipolar diffusion and sheaths in a bounded plasma
I am currently working through an introductory text book on plasma physics, and I have encountered two topics that I separately understand but seem to be at odds with one another. In a quasi neutral ...
0
votes
0answers
18 views
Electric Field within and outside a plasma ball
According to the electric field strength's equation, electric field strength is inversely proportional to square of distance. Thus, electric field strength gets weaker as it is further away from the ...
0
votes
1answer
118 views
Splitting $CO_2$ as a plasma to remove it from the atmosphere
I am wondering if CO2 can be removed from the atmosphere by heating it up using the same lasers they use to make plasma when researching nuclear fusion, and then fire the plasma of oxygen and carbon ...
-2
votes
1answer
50 views
Gravitational and Electric Forces in the Movements of Planets [duplicate]
Now that we know about the electric nature of the cosmos, the question arises: "How much are planets affected by electric forces while moving through the universe?" We have been taught that the ...
1
vote
0answers
37 views
Plasma Maintenance
What are energy efficient ways that can be used to keep a plasma in its fully ionized mode while minimizing losses due to recombination?
Let’s say I have 1 mole of some material, and I need 15eV to ...
2
votes
1answer
51 views
Multiple Ion Species MHD
If I have a fully ionized plasma consisting of electrons and a mixture of different positive ion species of varying masses and charges...how can I use the MHD model to describe the plasma fluid motion,...
0
votes
0answers
18 views
Momentum mismatch on surface plasmon
I read Naturevolume 424, pages824–830 (2003).
There is following sentence.
"This increase in momentum is associated with the binding of the SP to the surface, and the resulting momentum mismatch ...
1
vote
1answer
52 views
Two questions about Langmuir probe current-voltage characteristics
When the surface of Langmuir probe is a plane, the I-V curve has a shape like that illustrated in this figure:
One can clearly note the existance of two regions of sauration, in which the current has ...
0
votes
1answer
53 views
Sampling Maxwell-Jüttner distribution for non-unity mass and speed of light
I am trying to sample Maxwell-Jüttner distribution using the Sobol method as described in Zenitani Loading relativistic Maxwell distributions in particle simulations (2015). Equation (2) in the paper ...
1
vote
1answer
24 views
Laser Solid Interaction
Can a continuous output laser fully ionize a surface to produce a plasma? I know of femtosecond laser pulses that do cause Coulomb Explosions, but what about in the case of continuous wave (CW) laser ...
0
votes
0answers
24 views
Plasma Condensation
How can a plasma with ion temperature in the order of ~10^5 K be cooled to form a solid? Is there such thing as “plasma deposition,” where you could deposit arelatively hot dense plasma on a colder ...
2
votes
0answers
17 views
Simplified laser wakefield accelerator model
so I am working on a summer essay and trying to work my way through the following online material I found; https://www.cockcroft.ac.uk/wp-content/uploads/2018/04/LWFA_comp.pdf.
However, there are ...
0
votes
0answers
26 views
Generation of plasma waves
In any introductory plasma physics text books, one will encounter a host of plasma waves. However, often in research articles one can see that generation of any plasma waves say e.g. Langmuir waves, ...
3
votes
1answer
49 views
Collisionless Plasma Assumptions
When can I assume that plasma is collisionless? How is the presumption of a plasma being "collisionless" depend on other parameters such as ion density and ion and electron temperature?
1
vote
5answers
172 views
Can air be ionized using microwaves?
I've read about the concept of a laser induced plasma channel where air can be ionized to form a plasma using laser light. Can this be done or is it hypothetically possible to ionize air with ...
1
vote
1answer
31 views
Why does the ion and electron currents saturate in Langmuir probes?
From the I-V characteristics of the Langmuir probes used in Plasma diagnostics, we can calculate the plasma density, temperature, etc from the ion and electron saturation currents. But why does the ...
1
vote
0answers
11 views
Does anyone knows where can I find the phase diagram of oxygen free copper (OFC or OFHC)?
I am having problems with a niobium deposition I made on a substrate. I increased the temperature to 500 degrees celsius and in theory the film should have a better quality. However this wasn't the ...
0
votes
1answer
38 views
Nature of plasma of the early intergalactic medium
Please I have a question to ask about the nature of plasma of the early intergalactic medium at large redshifts.
We known that the most important unmagnetized cosmic plasma is the early intergalactic ...
1
vote
1answer
51 views
What's the difference between shock waves and acoustic waves?
What's the difference between shock waves and acoustic waves?
I tried and searched around this subject, but I could not find any relative article about it. Please help me find a proper answer.
3
votes
1answer
30 views
How is a plasma with only nuclei and electrons different?
How is a plasma with only bare nuclei and electrons, different from a plasma where the positive ions have some electrons attached?
I have looked in plasma physics books but never seen any mention of ...
0
votes
2answers
28 views
What is causing plasma confinement instability according to Erik Witalis?
Erik Witalis mentions problems with traditional plasma confinement like the one in tokamaks and particle beams. Instead he mentioned a different technique.
What is the problem with plasma confinement ...
0
votes
0answers
41 views
How much energy does it take to form a plasma channel with a laser?
The usage is for something like this https://en.wikipedia.org/wiki/Electrolaser
I know that the laser is powered for an instant in which a plasma channel is formed for the electricity to flow through,...
0
votes
0answers
28 views
Criteria for electrostatic approximation in microscopic/kinetic plasmas
I started pondering about the electrostatic approximation in relation to plasmas, where a particle's motion $\mathbf x(t)$ is governed by the Lorentz force:
$$
m\ddot{\mathbf x}=q(\mathbf E+\dot{\...
1
vote
0answers
32 views
Discrepancy when using Saha equation?
I was trying to calculate the level of ionization using Saha eq. for hydrogen gas at 1 atm pressure at 10 000 K and upwards. I used an Excel spreadsheet and the values I get don't match with other ...
4
votes
2answers
129 views
How does the Earth's magnetic field protect it from the solar wind?
Several sources (see linked questions at the end) say that earth's magnetic field shields us from the solar wind.
The general consensus is that without earth's magnetic field, the atmosphere would be ...
1
vote
2answers
73 views
Lasers for plasma
Recently I had the same idea as given at A question about the properties of plasma and its potential use in recycling, or a similar one, rather. The basic idea is: could you turn stuff into plasma ...
4
votes
1answer
96 views
Why the geomagnetic field become stronger when solar wind is stronger?
The following description is from the webpage of Niels Bohr Institue's Former Centre for Ice and Climate
The Earth reacts to the solar wind by increasing the strength of the shielding magnetic ...
0
votes
1answer
38 views
Magnetic compression of plasma?
What is the mechanism for plasma compression in the video below?
I provide a still from the video and a link to the actual video on YouTube.
https://www.youtube.com/watch?v=gsjWGz3YE5o
BTW, is ...
0
votes
1answer
22 views
How is the electron (&ion) temperature measured in plasmas using Langmuir probes?
I want to know the concept behind the temperature measurement and what exactly the "probe" does apart from introducing potential in the plasma.
Also, while deriving an expression for electron ...
1
vote
1answer
63 views
Electric field of electron in alternating potential
I am considering the case of an electron placed in an alternating sinusoidal potential, of frequency 13.56 MHz (frequency typically used for RF plasma generation).
Suppose I have a simple 1D set up, ...
-3
votes
1answer
224 views
How do we find the equation for the gyrating motion of a particle in a uniform magnetic field and a non-uniform Electric field? [closed]
Considering the gyrating motion is not negligible and also retaining the guiding center drift, how do we get the trajectories x(t),y(t),z(t) of the particle?
In this case is the variation in the ...
1
vote
0answers
21 views
Question about spatial uniformity of particle density in plasmas (from Bellan)
Early in Bellan he asks us to consider a finite-temperature plasma and assume that the ion and electron densities are initially equal and spatially uniform. He approaches the problem of calculating ...
3
votes
1answer
38 views
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)...
1
vote
2answers
26 views
Problem while constructing langmuir probe
I am working on DC glow discharges and want to construct a langmuir probe. Circuit I am using is as shown in the picture
Also, I am applying ~1KV across cathode and anode.
Problem I am facing is that ...
