150,145 research outputs found
Laboratory investigations of space-relevant, self-organizing MHD plasmas
Pulsed power technology is used to produce transient MHD-regime plasmas having topology and dynamical behavior similar to solar and astrophysical plasmas. These plasmas are not exact scale models, but exhibit many behaviors similar to actual solar and astrophysical plasmas, for example, collimation, kinking, and jet motion. These plasmas can also display an interaction between MHD-dynamics and non-MHD particle orbit behavior
Electromagnetic response of strongly coupled plasmas
We present a thorough analysis of the electromagnetic response of strongly
coupled neutral plasmas described by the gauge/gravity correspondence. The
coupling of the external electromagnetic field with the tower of quasi-normal
modes of the plasmas supports the presence of various electromagnetic modes
with different properties. Among them we underline the existence of negative
refraction with low dissipation for a transverse non-hydrodynamical mode.
Previous hydrodynamical approaches have shown the ubiquitous character of
negative refraction in charged plasmas and the absence thereof in neutral
plasmas. Our results here extend the analysis for neutral plasmas beyond the
hydrodynamical regime. As an application of these new insights we briefly
discuss the case of the quark gluon plasma in the temperature dominated regime.Comment: 29 pages, 15 figure
Turbulence and structure formation in complex plasmas and fluids
The formation and evolution of nonlinear and turbulent dynamical structures
in two-dimensional complex plasmas and fluids is explored by means of
generalised (drift) fluid simulations. Recent numerical results on turbulence
in dusty magnetised plasmas, strongly coupled fluids, semi-classical
("quantum") plasmas and in rotating quantum fluids are reviewed and discussed
Self-Organized Criticality in Compact Plasmas
Compact plasmas, that exist near black-hole candidates and in gamma ray burst
sources, commonly exhibit self-organized non-linear behavior. A model that
simulates the non-linear behavior of compact radiative plasmas is constructed
directly from the observed luminosity and variability. The simulation shows
that such plasmas self organize, and that the degree of non-linearity as well
as the slope of the power density spectrum increase with compactness. The
simulation is based on a cellular automaton table that includes the properties
of the hot (relativistic) plasmas, and the magnitude of the energy
perturbations. The plasmas cool or heat up, depending on whether they release
more or less than the energy of a single perturbation. The energy release
depends on the plasmas densities and temperatures, and the perturbations
energy. Strong perturbations may cool the previously heated plasma through
shocks and/or pair creation.
New observations of some active galactic nuclei and gamma ray bursters are
consistent with the simulationComment: 9 pages, 5 figures, AASTeX, Submitted to ApJ
Water bath calorimetric study of excess heat generation in 'resonant transfer' plasmas
Water bath calorimetry was used to demonstrate one more peculiar phenomenon
associated with a certain class of mixed gas plasmas termed resonant transfer,
or RT plasmas. Specifically, He/H2 (10%) (500 mTorr), Ar/H2 (10%) (500 mTorr),
and H2O(g) (500 and 200 mTorr) plasmas generated with an Evenson microwave
cavity consistently yielded on the order of 50% more heat than non RT plasma
(controls) such as He, Kr, Kr/H2 (10%), under identical conditions of gas flow,
pressure, and microwave operating conditions. The excess power density of RT
plasmas was of the order 10 W / cm-3. In earlier studies with these same RT
plasmas it was demonstrated that other unusual features were present including
dramatic broadening of the hydrogen Balmer series lines, unique vacuum
ultraviolet (VUV) lines, and in the case of water plasmas, population inversion
of the hydrogen excited states. Both the current results and the earlier
results are completely consistent with the existence of a hitherto unknown
exothermic chemical reaction, such as that predicted by Mills, occurring in RT
plasmas.Comment: 30 pages, 2 tables, 5 figure
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