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Plasma cosmology is a non-standard cosmological model based on the electromagnetic properties of astrophysical plasmas. The stars and essentially all of the space between them is filled with plasma. Plasma cosmology attempts to explain the large scale structure of the universe, from galaxy formation to the cosmic microwave background in terms of this ubiquitous phase of matter. The theory was largely developed by plasma physicist Hannes Alfvén and subsequently developed by other plasma physicists such as Anthony Peratt and Eric Lerner.

The properties of plasmas are well modelled by the science of magnetohydrodynamics (MHD), the developement of which won Alfvén the Nobel Prize in 1970. MHD generally treats a plasma as an a perfectly conducting ideal fluid with little or no resistivity, and which Alfvén called a "magnetic field description". But based on his experimental work, Alfvén's also applied an "electric current description" to plasmas, whose properties are less well-known, such as Birkeland currents (field-align currents), double layers (charge separation regions), certain classes of plasma instabilities, and chemical separation in space plasmas. An extended version of MHD encompassing an electric field description and some of these more complex phenomena is called Hall-magnetohydrodynamics (Hall-MHD or HMHD).

Plasma cosmology can be thought to have originated in 1913 when Kristian Birkeland proposed that the Solar Wind consisted of ions (ie. a plasma). In 1937, his work was subsequently revived and developed by Hannes Alfvén, who argued that if plasma pervaded the universe, then it could carry electric currents that could generate a galactic magnetic field. Many years afterward, space was still thought to be a vacuum. Later Alfvén had also theorised the existence of anti-plasma or ambiplasma, but the idea never came into favour.

Overview

Space plasmas contain equal numbers of electrons (negative ions) to positive ions (eg. mainly hydrogen ions, or protons, H+), so that they are electrically neutral overall. Plasma are also highly conductive, so that even if charges become unbalanced, electrons can move quickly to neutralise the charge. Movement of electrons is characterized by electric current.

The heliospheric current sheet is an example of the influence of the Sun's magnetic field on the interplanetary medium (a plasma), resulting in a sheet of electric current that extends from the Sun to the outer reaches of the Solar System. The range of electric fields in the interplanetary medium is of the order of about 10-meters; the current sheet extends over the diameter of the Solar System, some 1x10m.

Electromagnetic forces in plasmas

The electromagnetic force between two charged particles, is many times – 10 times for two electrons -- greater than the force of gravity between them. As the long-accepted functional definition of plasmas is that they are neutral on large scales, the electric forces in them have limited range, just as the gravitational force is the only long range force we experience on Earth.

The local range of electric fields in a plasma is defined by the Debye Length, and is typically about 1 cm in the ionosphere, 10m in the Solar Wind, and 10km in the intergalactic medium. But despite this, plasmas are able to create more complex phenomena (see below) that exceed the Debye Length by many orders of magnitude. Examples include:

• Birkeland Currents, such as those that feed the aurora above Earth. They are typically several thousand kilometers long, and carry terawatts of power. Ref.

• The Heliospheric Current Sheet (also called Interplanetary Current Sheet), a ballerina-shaped sheet of current that extends outward from the Sun throughout the Solar System. Ref

• Drift Currents, which occur wherever there is a net difference in motion of electrons and ions (see also Guiding center and Drifts). Alfvén notes that (a) The gravitation drift may cause chemical separation to occur since it depends on the mass of the charged particle. (b) Inertia drift transfers kinetic energy into electromagnetic energy, and vice versa. (c) All the drifts produce an electric current (a drift current), except for the electric field drift since it does not depend on the sign of the charge.

Microwave background

In the mid-1990s, a few mainstream cosmologists became interested in plasma cosmologies. This interest rapidly waned as precise measurements of the cosmic microwave background (CMB), such as those by COBE, and the primordial helium abundances agreed well with the big bang theory.

Both Anthony Peratt and Eric J. Lerner have proposed that plasma cosmology could be consistent with the CMB. In particular, Lerner has shown that plasma cosmology can generate a background by synchrotron radiation. This model fails to predict the CMB anisotropy peaks in the power spectrum or the precise black-body nature of the spectrum. In particular, it fails to predict the 1 degree mode on the sky or the strength of this feature.

Redshifts

Although there are many local redshifting mechanisms observed in laboratory experimentation with plasmas, one problem in using a majority of them to explain cosmological redshifts is that it is difficult to account for a change in the energy of a photon going through plasma without photon scattering (changing the photon's direction of propagation.) In some non-linear optical phenomena there are forms of scattering in which the direction of propagation of the photons is not changed. Specifically, one promising candidate for astrophysical application is Forward Brillouin Scattering, found locally in laser fusion devices, as an example. This form of forward scattering causes a redshift and a broadening of spectral lines without changing the direction of propagation of the incident light.

Alfvén's model

Nobel laureate Hannes Alfvén's model of plasma cosmology can be divided into two distinct areas. (1) Cosmic Plasma, his empirical description of the Universe based on the results from laboratory experiments on plasmas (2) ambiplasma theory, based on a hypothetical matter/antimatter plasma.

Alfvén's Cosmic Plasma

Building on the work of Kristian Birkeland, Alfvén's research on plasma led him to develop the field of magnetohydrodynamics (MHD), a field of work that mathematically models plasma as fluid, and for which he won the Nobel Prize for Physics in 1970. MHD is readily accepted and used by astrophysicists and astronomers to describe many celestial phenomena.

But Alfvén felt that many other characteristics of plasmas played a more significant role in cosmic plasmas. These include:

• Scaleability of plasma where the properties laboratory plasmas can be applied to cosmic plasmas
• Birkeland currents (electric currents) that form electric circuits in space, stored energy and transport energy from one region to another (see diagram below)
• Plasma double layers, charge separation regions that also accelerate ions to relativistic velocities and produce synchrotron radiation
• Instabilities such as the Bennett pinch (Z-pinch) that produces plasma cables (magnetic ropes)
• The cellular structure of plasma, whereby a plasma of a certain set of properties tends to form a spherical or tear-drop shaped region in space, such as the heliosphere, or Earth's plasmasphere.

History

In 1913, Norwegian explorer and physicist Kristian Birkeland may have been the first to predict that space is a plasma. He wrote: "It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. We have assumed that each stellar system in evolutions throws off electric corpuscles into space. It does not seem unreasonable therefore to think that the greater part of the material masses in the universe is found, not in the solar systems or nebulae, but in "empty" space. (See "Polar Magnetic Phenomena and Terrella Experiments" in The Norwegian Aurora Polaris Expedition 1902-1903 (publ. 1913, p.720)

Future

Plasma cosmology is not an established scientific theory, and even most advocates agree the explanations provided are much less complete than those of conventional cosmology. Within plasma cosmology, there have been no published papers which make predictions on the primordial helium abundance (although this subject is addressed in Lerner's book), or which calculate correlation functions.

Figures in plasma cosmology

The following physicists and astronomers helped, either directly or indirectly, to develop this field:

• Hannes Alfvén - Along with Birkeland, fathered Plasma Cosmology and was a pioneer in laboratory based plasma physics. Received the only Nobel Prize ever awarded to a plasma physicist.
• Halton Arp - Astronomer famous for his work on anomalous redshifts, "Quasars, Redshifts and Controversies".
• Kristian Birkeland - First suggested that polar electric currents are connected to a system of filaments (now called "Birkeland Currents") that flowed along geomagnetic field lines into and away from the polar region. Suggested that space is not a vacuum but is instead filled with plasma. Pioneered the technique of "laboratory astrophysics", which became directly responsible for our present understanding of the aurora.
• Eric Lerner - Claims that the intergalactic medium is a strong absorber of the cosmic microwave background radiation with the absorption occurring in narrow filaments. Postulates that quasars are not related to black holes but are rather produced by a magnetic self-compression process similar to that occurring in the plasma focus.
• Anthony Peratt - Developed computer simulations of galaxy formation using Birkeland currents along with gravity. Along with Alfven, organized international conferences on Plasma Cosmology.
• Nikola Tesla - Developed the rotating magnetic field model.
• Gerrit L. Verschuur - Radio astronomer, writer of "Interstellar matters : essays on curiosity and astronomical discovery" and "Cosmic catastrophes".

See also

• Cosmology : Non-standard cosmology, Timeline of cosmology
• Physics : Cosmic microwave background radiation, Theoretical astrophysics, Theoretical physics, Plasma physics, Rotating magnetic fields, Astrophysical plasma, Magnetohydrodynamics, Pathological science
• Other: List of protosciences, Quasars, Redshifts and Controversies
• The ambiplasma model, or the Alfvén-Klein model, is the original model of plasma cosmology.
• Electric Universe model, which is another non-standard cosmology based on plasma physics that incorporates Velikovskian catastrophism as well as a non-standard model of stellar physics called the "Electric Star hypothesis." It does not appear to be taken seriously by most plasma cosmologists. It is not mentioned in the books, websites, or journal publications of Alfven, Peratt, Lerner, et al. (With one exception: On page 4 of his book The Big Bang Never Happened, Lerner stated "hat I describe here is not... a Velikovskian fantasy." This may serve as an indicator as to how plasma cosmologists view Velikovskians.) Plasma cosmologists have likewise ignored the electric star model, and have always accepted the standard (fusion) theory.

Links and resources

• Alfven, H. "Cosmogony as an extrapolation of magnetospheric research"
• Alfven, H. "On hierarchical cosmology"
• Wright, E. L. "Errors in Lerner's Cosmology".
• Lerner, E. J. "Dr. Wright is Wrong". Lerner's reply to the above.
• Peratt, Anthony, "Plasma Universe". (Related Papers)
• Wurden, Glen, "The Plasma Universe". Los Alamos National Laboratory. University of California (U.S. Department of Energy). (General Plasma Research)
• Marmet, Paul, "Big Bang Cosmology Meets an Astronomical Death". 21st Century, Science and Technology,Washington, D.C.
• Eastman, Timothy E., "Plasma Astrophysics". Plasmas International. (References, Parameters, and Research Centers links.)
• Goodman, J., "The Cosmological Debate".
  • Goodman, J., "The Case for Plasma Cosmology"
• Heikkila, Walter J. "Elementary ideas behind plasma physics", from a Special Issue of Astrophysics and Space Science" Dedicated to Hannes Alfvén on 80th Birthday

Publications

• IEEE Xplore, IEEE Transactions on Plasma Science, 18 issue 1 (1990), Special Issue on Plasma Cosmology.
• G. Arcidiacono, "Plasma physics and big-bang cosmology", Hadronic Journal 18, 306-318 (1995).
• J. E. Brandenburg, "A model cosmology based on gravity-electromagnetism unification", Astrophysics and Space Science 227, 133-144 (1995).
• J. Kanipe, "The pillars of cosmology: a short history and assessment". Astrophysics and Space Science 227, 109-118 (1995).
• O. Klein, "Arguments concerning relativity and cosmology," Science 171 (1971), 339.
• W. C. Kolb, "How can spirals persist?," Astrophysics and Space Science 227, 175-186 (1995).
• E. J. Lerner, "Intergalactic radio absorption and the Cobe data", Astrophys. Space Sci. 227, 61-81 (1995)
• E. J. Lerner, "On the problem of Big-bang nucleosynthesis", Astrophys. Space Sci. 227, 145-149 (1995).
• B. E. Meierovich, "Limiting current in general relativity" Gravitation and Cosmology 3, 29-37 (1997).
• A. L. Peratt, "Plasma and the universe: Large-scale dynamics, filamentation, and radiation", Astrophys. Space Sci. 227, 97-107 (1995).
• A. L. Peratt, "Plasma cosmology", IEEE T. Plasma Sci. 18, 1-4 (1990).
• C. M. Snell and A. L. Peratt, "Rotation velocity and neutral hydrogen distribution dependency on magnetic-field strength in spiral galaxies", Astrophys. Space Sci. 227, 167-173 (1995).

Related Books

• H. Alfvén, Worlds-antiworlds: antimatter in cosmology, (Freeman, 1966).
• H. Alfvén, Cosmic Plasma (Reidel, 1981) ISBN 9027711518
• E. J. Lerner, The Big Bang Never Happened, (Vintage, 1992) ISBN 067974049X
• A. L. Peratt, Physics of the Plasma Universe, (Springer, 1992) ISBN 0387975756

• Cosmology
• Protoscience
• Space plasmas