1,913 research outputs found
Signatures of two-step impurity mediated vortex lattice melting in Bose-Einstein Condensates
We simulate a rotating 2D BEC to study the melting of a vortex lattice in
presence of random impurities. Impurities are introduced either through a
protocol in which vortex lattice is produced in an impurity potential or first
creating the vortex lattice in the absence of random pinning and then cranking
up the (co-rotating) impurity potential. We find that for a fixed strength,
pinning of vortices at randomly distributed impurities leads to the new states
of vortex lattice. It is unearthed that the vortex lattice follow a two-step
melting via loss of positional and orientational order. Also, the comparisons
between the states obtained in two protocols show that the vortex lattice
states are metastable states when impurities are introduced after the formation
of an ordered vortex lattice. We also show the existence of metastable states
which depend on the history of how the vortex lattice is created.Comment: Accepted in Euro. Phys. Let
The study of Microstructure of III-V Polar on Non-Polar Heterostructures By HRXRD
In this article, we report on the detailed high resolution x-ray diffraction data analysis of three GaAs films deposited by metal organic vapour phase epitaxy on Si substrates. In the GaAs/Si films the effect of anti phase domains is seen by the selective broadening of (002) and (006) reflections. Further as the (006) reflection is a very weak reflection, such films cannot be analyzed by conventional Williamson-Hall plots using (002), (004) and (006) reflections. We find that using (111), (333) and (444) reflections it is possible to use the standard Williamson-Hall analysis and extract parameters related to the microstructure of the films. We have also carried out the analysis to determine the tilt and twist between the mosaic blocks after correcting for the effects of the finite lateral coherence length.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/930
Weak turbulence theory of the non-linear evolution of the ion ring distribution
The nonlinear evolution of an ion ring instability in a low-beta
magnetospheric plasma is considered. The evolution of the two-dimensional ring
distribution is essentially quasilinear. Ignoring nonlinear processes the
time-scale for the quasilinear evolution is the same as for the linear
instability 1/t_ql gamma_l. However, when nonlinear processes become important,
a new time scale becomes relevant to the wave saturation mechanism. Induced
nonlinear scattering of the lower-hybrid waves by plasma electrons is the
dominant nonlinearity relevant for plasmas in the inner magnetosphere and
typically occurs on the timescale 1/t_ql w(M/m)W/nT, where W is the wave energy
density, nT is the thermal energy density of the background plasma, and M/m is
the ion to electron mass ratio, which has the consequence that the wave
amplitude saturates at a low level, and the timescale for quasilinear
relaxation is extended by orders of magnitude
Kaneko et al. Reply
Comment on "Drift-Wave Instability Excited by Field-Aligned Ion Flow Velocity Shear in the Absence of Electron Current
The study of Microstructure of III-V Polar on Non-Polar Heterostructures By HRXRD
In this article, we report on the detailed high resolution x-ray diffraction data analysis of three GaAs films deposited by metal organic vapour phase epitaxy on Si substrates. In the GaAs/Si films the effect of anti phase domains is seen by the selective broadening of (002) and (006) reflections. Further as the (006) reflection is a very weak reflection, such films cannot be analyzed by conventional Williamson-Hall plots using (002), (004) and (006) reflections. We find that using (111), (333) and (444) reflections it is possible to use the standard Williamson-Hall analysis and extract parameters related to the microstructure of the films. We have also carried out the analysis to determine the tilt and twist between the mosaic blocks after correcting for the effects of the finite lateral coherence length.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/930
Co-existence of Whistler Waves with Kinetic Alfven Wave Turbulence for the High-beta Solar Wind Plasma
It is shown that the dispersion relation for whistler waves is identical for
a high or low beta plasma. Furthermore in the high-beta solar wind plasma
whistler waves meet the Landau resonance with electrons for velocities less
than the thermal speed, and consequently the electric force is small compared
to the mirror force. As whistlers propagate through the inhomogeneous solar
wind, the perpendicular wave number increases through refraction, increasing
the Landau damping rate. However, the whistlers can survive because the
background kinetic Alfven wave turbulence creates a plateau by quasilinear
diffusion in the solar wind electron distribution at small velocities. It is
found that for whistler energy density of only ~10^-3 that of the kinetic
Alfven waves, the quasilinear diffusion rate due to whistlers is comparable to
KAW. Thus very small amplitude whistler turbulence can have a significant
consequence on the evolution of the solar wind electron distribution function
Quasilinear Evolution of Kinetic Alfven Wave Turbulence and Perpendicular Ion Heating in the Solar Wind
The measured spectrum of kinetic Alfven wave fluctuations in the turbulent
solar wind plasma is used to calculate the electron and ion distribution
functions resulting from quasi-linear diffusion. The modified ion distribution
function is found to be unstable to long wavelength electromagnetic ion
cyclotron waves. These waves pitch angle scatter the parallel ion velocity into
perpendicular velocity which effectively increases the perpendicular ion
temperature.Comment: 14 pages, 3 figure
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