Plasma
Plasma is ionised matter — a gas in which enough electrons have been stripped from atoms that the free charges determine its behaviour — and is usually counted as the fourth state of matter alongside solid, liquid and gas.
The standard account
A plasma is quasi-neutral over distances larger than the Debye length but responds collectively to electric and magnetic fields, so it conducts electricity, carries currents, supports its own waves and can be confined or pinched magnetically. Irving Langmuir gave it the name in 1928. Because it is electrically conducting, a magnetic field embedded in a plasma is dragged with the flow when the conductivity is high (the "frozen-in" approximation), which is the basis of magnetohydrodynamics. Hannes Alfvén developed MHD and predicted the waves that carry his name; he received the Nobel Prize in Physics in 1970.
Plasma is not exotic. Stars, the solar wind, the interstellar and intergalactic medium, nebulae, planetary ionospheres, lightning and fluorescent tubes are all plasmas, so the great majority of the ordinary (baryonic) matter we can see directly is in the plasma state. Mainstream astrophysics uses plasma physics constantly — in stellar interiors, accretion discs, pulsar magnetospheres, solar flares and galactic magnetic fields — but treats gravity as the organising force on the largest scales.
On this wiki
Category:Plasma gathers a large body of work arguing that electromagnetic forces have been systematically underweighted in cosmology, and that structures attributed to gravity, dark matter or exotic objects are better read as plasma phenomena: filaments, Birkeland currents, double layers and pinches.
- Anthony L Peratt, author of Physics of the Plasma Universe, is the central figure for the simulation side of the argument; his two-part Evolution of the Plasma Universe: I Double Radio Galaxies, Quasars, and Extragalactic Jets models radio galaxies and jets as interacting current filaments.
- Eric J Lerner argues the cosmological case in Plasma Universe: Beyond the Big Bang and related work, contesting the Big Bang on plasma and light-element grounds.
- Alfvén's own late position — that the idealisations he introduced were being applied far beyond their range of validity in astrophysics — is discussed in The Plasma Universe of Hannes Alfv.
- Wallace Thornhill and Donald E Scott are the wiki's principal Electric Universe authors, extending the argument to the solar system and to planetary surface features.
- Ari Brynjolfsson's Plasma Redshift Cosmology proposes that photons lose energy to plasma electrons, offering a Tired Light alternative to cosmological expansion; see also Plasma Theory of Hubble Redshift of Galaxies and Intergalactic Plasma.
- Laboratory and applied plasma work is also catalogued here, including Dusty Plasma and a range of Cold Fusion and discharge experiments.
A distinction worth keeping: the observational claim that the universe is threaded with currents and magnetic fields is not itself heterodox — galactic and cluster magnetic fields are measured — and papers here vary widely in how far beyond that they go. Alfvén's methodological criticism of frozen-in field assumptions is a different and stronger argument than the claim that gravity plays no significant cosmological role.