Ultracold Gas Mimics Ultrahot Plasma
http://www.sciencedaily.com/releases/20 ... 151457.htm
http://www.iop.org/EJ/abstract/0022-3727/35/17/311ScienceDaily (Feb. 15, 2009) — Several years after Duke University researchers announced spectacular behavior of a low density ultracold gas cloud, researchers at Brookhaven National Laboratory have observed strikingly similar properties in a very hot and dense plasma "fluid" created to simulate conditions when the universe was about one millionths of a second old.
The plasma was formed at a colossal 2 million degrees Kelvin temperatures within Brookhaven's Relativistic Heavy Ion Collider (RHIC). The gas cloud was cooled to only .1 millionths of a degree Kelvin temperatures using a laser light "trap" and magnetic field at Duke. But both drastically different systems expanded something like exploding cigars. And their constituent matter also showed signs of flowing almost free of any viscosity -- a "nearly perfect" fluid, said Duke physics professor John Thomas.
"There's about 19 orders of magnitude difference in temperature and about 25 orders of magnitude difference in density, but the commonality of both is almost zero viscosity flow," said Thomas.
Thomas reported on his laboratory's experiments with "fermion" gases and their possible relevance to RHIC's "quark-gluon plasma" research as well as to string theory during a Feb. 15 symposium organized by Brookhaven during the American Association of Science's 2009 Annual meeting, held in Chicago.
In a November, 2002 report in the research journal Science, Thomas and co-researchers described what happened after they confined a cloud of lithium-6 atoms and cooled them to 100 billionths of a degree above absolute zero. When the ultracooled, cigar-shaped cloud was then released from the trap, it expanded "anisotropically," meaning "fastest along the direction that was initially narrow," he recalled.
Lithium atoms are of the fermion class, meaning that that their spin-states normally make them keep more of a distance from each other than their chummier counterpart class of atoms -- the bosons. But under the extreme conditions of his experiments, even fermions find ways to collide to form what are called "strong interactions," he said.
Brookhaven's RHIC is designed to smash gold atoms together near the speed of light. Its goal is to create energies colossal enough to break apart their nuclei into an ultrahot gas of the most fundamental particles, "naked" quarks and gluons. Theoreticians believe such a "quark-gluon plasma" has not existed since a split-second after the Big Bang.
As the results of those experiments began to surface in April, 2005, RHIC experimenters found that "the cigar shaped plasma looked very much like the cigar- shaped cloud in our trap," Thomas said. That cloud also expanded anisotropically in keeping with what theorists in the field had predicted. Researchers also found that this plasma behaved as an almost-perfect fluid. Meanwhile, further work by Thomas's group has documented almost viscosity-free fluid states in its cold fermion gases.
Thomas noted that quarks themselves are also fermions. "So there's quite a broad overlap, and a genuine common interest in these two patterns. We don't have exactly the same system as at RHIC. But in a broad sense there are similarities that could be exploited to get some insight."
Meanwhile, researchers involved in string theory have also approached Thomas about similarities between his fermion findings and the predicted behavior of what those theorists call "strongly interacting quantum fields," he said. "It's not clear, though, that the prediction has any relevance to Fermi atoms colliding in a trap. However, the closeness of the initial cold gas measurements to the predictions is striking."
Elements of string theory aim at bridging the gap between quantum mechanics and general relativity by proposing that the true fundamental particles are actually ultra-tiny strings vibrating in multiple dimensions
Abstract. Application of the inductively coupled thermal plasma (ICTP) technique was proposed for investigating plasma-quenching efficiency of various gases including the arc-quenching medium of SF6. The ICTP enables us to study fundamentally the effect of gas injection on thermal plasma without any impurities because it has no electrode. Seven kinds of gases including CO2, SF6 and environmentally benign gases (N2, O2, air, He and H2) were injected into Ar ICTP. Spectroscopic observation was carried out in order to investigate a change in the excited state of Ar atoms due to addition of these gases. Radial distributions of the radiation intensity of Ar spectral lines and the temperature of Ar ICTP were estimated. It was found that 10% CO2 addition causes a remarkable decline of the radiation intensity and temperature at any radial position, similarly to 2% SF6 addition. Two-dimensional local thermal equilibrium modelling for Ar ICTP also revealed that CO2 causes temperature decay more than the other gases of N2, O2, air, He and H2 except SF6.
So basically my inspiration was that the charged partcles, ions, making up the plasma of various content, (not that I actually understand if what I'm suggesting is even possible but anyway), shouldn't oxygen plasma quantities/currents be attracted to hydrogen plasma quantities/currents, or various relatively elemantally pure plasmas interact chemically in a similar way.Low-dielectric-constant SiOF films are deposited using O2/SiF4 and O2/FSi(OC2H5)3 mixtures in a helicon plasma reactor, and good quality films can be obtained without intentional heating or biasing of the substrate. Optical emission spectroscopy (OES) is used to study the relation between the relative densities of the radicals and the film properties. The OES data imply that the source gases are highly dissociated above the RF power of 900 W where the helicon mode is generated. Consequently, the mechanism of helicon plasma chemical vapor deposition (CVD) is different from that of thermal CVD. In the case of thermal CVD, the source gases react chemically on the high-temperature substrate and form films. However, in the case of helicon wave plasma CVD, the source gases are highly dissociated in the high-density plasma and many radicals are produced, that react on the substrate. SiOF films are made in the case of O2/SiF4 but CF/SiOF composite films are made in the case of O2/FSi(OC2H5)3, where FSi(OC2H5)3 is highly dissociated in plasma and C participates in the film formation. Films with a low dielectric constant of below 3.0 can be made.
