plasmas Definition and 23 Threads

Plasma (from Ancient Greek πλάσμα (plásma) 'moldable substance') is one of four fundamental states of matter, characterized by the presence of a significant portion of charged particles in any combination of ions or electrons. It is the most abundant form of ordinary matter in the universe, being mostly associated with stars, including the Sun.
Extending to the rarefied intracluster medium and possibly to intergalactic regions, plasma can be artificially generated by heating a neutral gas or subjecting it to a strong electromagnetic field.The presence of charged particles makes plasma electrically conductive, with the dynamics of individual particles and macroscopic plasma motion governed by collective electromagnetic fields and very sensitive to externally applied fields. The response of plasma to electromagnetic fields is used in many modern devices and technologies, such as plasma televisions or plasma etching.Depending on temperature and density, a certain number of neutral particles may also be present, in which case plasma is called partially ionized. Neon signs and lightning are examples of partially ionized plasmas.
Unlike the phase transitions between the other three states of matter, the transition to plasma is not well defined and is a matter of interpretation and context. Whether a given degree of ionization suffices to call a substance 'plasma' depends on the specific phenomenon being considered.

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  1. ZX.Liang

    I Some reasoning about Alfvén’s frozen-in flux theorem

    Alfvén’s theorem is very famous in plasma physics. It is also often used in astrophysics. The link in Wiki: https://en.wikipedia.org/wiki/Alfv%C3%A9n%27s_theorem However, after a series of continuous reasoning, it seems that this theorem has problem. What errors can be hidden in the reasoning...
  2. zaki belh

    A Question about kinetic theory and hydrodynamics (in plasmas)

    It is usual, in plasma physics, to combine the kinetic description for electron fluid and the hydrodynamic description for ion fluid, when studying the plasma properties or the dynamics of the electrostatic waves. I am wondering what are the physical meaning and limits of such an approach. Thanks.
  3. P

    A Notes on Cosmic rays - wave interactions in plasmas

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  4. T

    New approach to stabilize fusion plasmas

    https://phys.org/news/2019-01-scientists-stabilizes-fusion-plasmas.html By applying more RF power to the unstable 'bubbles' that form in the plasmas.
  5. S

    How do microwave plasmas work?

    I'm new to PF, I have an engineering background, but am trying to understand how microwave plasmas are generated. I'm trying to work out if a tuned microwave waveguide can create a plasma in a specific point in the waveguide say over 30 seconds as the microwave energy heats up the waveguide thus...
  6. chandrahas

    Do force drifts occur in highly collisional plasmas

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  7. T

    Highly collisional yet low resistivity plasmas

    In approximations for the applicability of ideal MHD to plasmas, it states that plasmas are considered highly collisional to permit the assumption that the plasma (i.e. electrons) follow a Maxwellian velocity distribution. Although is not resistivity based on collisions in the plasma? If there...
  8. T

    Does Centrifugal Force Cause Curvature Drift in Plasmas?

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  9. 1

    Instruments to measure plasmas besides Langmuir probes?

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  10. I

    Can all elements be turned into plasma?

    I'm not sure where to post this so forgive me if the is the wrong place. Can any element be a plasma or only certain ones? Could you make iron plasma?
  11. F

    Looking for research which encompasses both plasmas and fission.

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  12. Q

    Book on Diamagnetic drifts in Plasmas within Magnetic Fields

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  13. Astronuc

    Astrophysics Physics Of Space Plasmas: An Introduction, 2nd Ed, by George Parks

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  14. E

    Exploring Dusty Plasmas: What Are They?

    what is really dust-laden plasmas? :)
  15. T

    Understanding Coulomb Force in Plasmas

    This may be a pretty dumb question. How is it possible for ions and electrons to coexist in plasma state. Shouldn't be there Coulomb force between them so that they would be bound together and become atoms?
  16. D

    Trying to apply electric current to plasmas in motion.

    How do you represent a certain mass of plasma (ions and free electrons) traveling inside a containment from point A to point B as "I", electrical current? Trying to make a connection, Doug Ettinger
  17. D

    The affect of different plasmas on each other

    What occurs if a higher velocity, denser plasma plowed through a less dense plasma traveling at a lower, but parallel velocity ? Do mutual magnetic or electric inductances between the two plasmas occur ? Regards, Doug Ettinger
  18. H

    Cylindrically symmetric plasmas and models for.

    Hi, I have currently been thinking about laser-plasma interaction and I have a simple model in mind. I am going to look for a cylindrically symmetric solution of a cylindrically symmetric laser beam (of radius R) hits a initially charge neutral plasma creating an electron beam in the plasma...
  19. N

    Levitation using microwave-induced plasmas

    Hi all, I came across this interesting paper the other night: http://www.odu.edu/~spopovic/index_files/pub/LevitationPaper.pdf An experiment was conducted involving the levitation of a Syrofoam object above a plasma created by a microwave horn. The following explanation given for the...
  20. T

    How Do Electric Fields Differ Between Plasma and Vacuum Sheaths?

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  21. mheslep

    Confinement of Thermalized plasmas: Why not E instead B?

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  22. P

    Exploring Magnetic Energy with Plasmas: A 11th Grader's Challenge

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  23. E

    Solving Plasmas and Magnetics Questions with John

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