Ambiplasma
In the history of Cosmology an ambiplasma is a hypothetical plasma containing a mixture of both Matter and Antimatter. This concept was developed as an alternative to the Big Bang theory. In this concept, the universe has always existed and has no "point" origin. Ambiplasma takes the form of proton-antiprotons (heavy ambiplasma) and electrons-positrons (light ambiplasma). Essentially the universe contains heavy symmetric ambiplasma with protective light ambiplasma, separated by the Leidenfrost effect.
Ambiplasmas can be relatively long-lived, as the component particles and antiparticles are too hot and too low-density to annihilate with each other rapidly. Ambiplasma is affected by condensing gravity waves and other expansive Radiation pressures. The universe undergoes expansion and contraction frames, over trillions of years, producing heavy ambiplasma (by the quantum flux on space-time) and light ambiplasma in the alternating phase. As matter and antimatter interact and annihilate, more electrons and positrons (among other radiations) are produced.
The concept originally was developed by Hannes Alfven in 1965 in his book Worlds-Antiworlds, and extended by Oskar Klein in 1971. It is called the symmetric Alfven-Klein model. The theory has generally fallen in disfavour, as precision measurements of the large scale structure of the universe are in fine agreement with the Lambda-CDM model of Big Bang.
Alfvén's Ambiplasma Theory
Alfvén proposed the first well-developed plasma cosmology model in 1965. In his model, the universe exists as a mixture of Matter and Antimatter which he called ambiplasma. The cellular regions of matter and antimatter can mutually annihilate, leaving protons and electrons. This can cause a rapid expansion of the region local to the annihilation, which Alfven considered as a possible explanation for the observed apparent expansion of the universe. The Alfvén model deals with the problem of cancellation explained above by postulating that the regions of matter and anti-matter are larger than the presently observable universe, and are separated by double-layers in the plasma. Alfvén stressed the importance of the cellular and filamentary nature of plasmas at any scale, from the laboratory to the galactic.Alfvén's model possesses a number of highly appealing properties. Firstly, it addresses the question of what happened before expansion. Alfvén postulated that the universe has always existed, and that the expansion we might now be seeing is merely a local phase of a much larger history. Secondly, the model does not invoke any exotic physics (other than antimatter, which has been verified on Earth in high-energy colliders), instead modelling the universe using the well-understood electromagnetic forces along with gravity. Indeed, Alfvén based his ideas on experimental work in plasma physics here on earth. He strongly advocated experimental work as a necessary and dominant part of any theory. Even in the field of earth-based plasma physics, he had to overcome the inertia of the purely theoretical approach among his colleagues, whose analysis could not make any accurate predictions.
Criticisms of Alfvén's model
Alfvén proposed that the bubble of matter we are in is larger than the observable universe. This brought the question of how one would go about testing the model if the very large structures that it predicts cannot be observed. However, many stuctures can be observed, such as intergalactic Birkeland currents, double-layers, velocity-selection effects at multiple scales, etc.Unfortunately, from a theoretical point of view, there remain a number of problems with Alfvén's model. Alfvén did not formalize his model to the point where it is possible to perform numerical simulations similar to those now routinely performed to model the behavior of early galaxies in the standard cosmology and which are used to predict the Correlation function of the universe. Instead, Alfvén, in his usual style, outlined a very general view of how galaxies are disc-generators. He was quite unconcerned with conforming his model so that it can make the same predictions as the Big Bang.
Although 3-D formation simulations of single galaxies have been performed using a plasma model (see articles by Anthony Peratt) wherein electromagnetic forces are taken into account along with gravitation, there have been no published papers which attempt to calculate correlation functions and therefore allow detailed comparison with observations. However, when one compares the simulation cross-section with radio isophotes of AGN, one sees a remarkable resemblance. This resemblance is not surprising, however, since it is well-understood that the high-energies associated with AGN should be similar to plasmas.
Another problem is, ironically, that plasma cosmologies depend on physics which is, while not completely well-understood, quite well-documented from laboratory experimentation. Because the standard Big Bang model involves physics that is poorly understood, one can adjust Big Bang models to fit observations by invoking wiggle room parameters and exotic physics, such as the existence of as-yet unobserved particles. Due to its empirical foundations (Alfven was a laboratory physicist at heart, developing power-transmission systems and the like), it is much harder to modify Alfvén's model to fit cosmological observations.
From an observational point of view, the gamma rays emitted by even small amounts of matter/antimatter annihilation should be easily visible using gamma ray telescopes. However, such gamma rays have not been observed. One could rescue this model by proposing, as Alfvén does, that the bubble of matter we are in is larger than the observable universe. This then brings up the question of how one would go about testing the model if the structures that it predicts cannot be observed. In order to test the model, one would have to find some signature of the model in current observations, and this requires that the model be formalized to the point where detailed quantitative predictions can be made. That opens the theoretical problem mentioned in the last paragraph.
See also: Hannes Alfvén, Plasma cosmology
Related: Antimatter, Big Bang, Non-standard cosmology
External references
- Alfvén, Hannes, "Worlds-Antiworlds: Antimatter in Cosmology". San Francisco and London, 1966.