pinecone/core-2020-05-10-deduplication huggingface dataset:
Stability boundary analysis of the dynamic voltage restorer in weak systems with dynamic loads

In this contribution, a stability analysis for a dynamic voltage restorer (DVR) connected to a weak ac\ud
system containing a dynamic load is presented using continuation techniques and bifurcation theory. The\ud
system dynamics are explored through the continuation of periodic solutions of the associated dynamic\ud
equations. The switching process in the DVR converter is taken into account to trace the stability regions\ud
through a suitable mathematical representation of the DVR converter. The stability regions in the Thevenin\ud
equivalent plane are computed. In addition, the stability regions in the control gains space, as well as the\ud
contour lines for different Floquet multipliers, are computed. Besides, the DVR converter model employed\ud
in this contribution avoids the necessity of developing very complicated iterative map approaches as in the\ud
conventional bifurcation analysis of converters. The continuation method and the DVR model can take into\ud
account dynamics and nonlinear loads and any network topology since the analysis is carried out directly\ud
from the state space equations. The bifurcation approach is shown to be both computationally efficient\ud
and robust, since it eliminates the need for numerically critical and long-lasting transient simulations
Harmonic balance-based control of a boost DC/AC converter

The achievement of step-up inversion with a boost DC/AC converter requires appropriate periodic references for inductor currents, which have to satisfy ordinary differential equations (ODE) of the Abel type. These are equations with highly unstable solutions for which the existence of periodic solutions remains unproved. Hence, the studies reported so far in this subject obtain periodic output voltages that approximately track the expected profile using different periodic current references that do not exactly satisfy the Abel ODE. However, neither an explanation of why are periodic output voltages still obtained, nor an assessment of the output voltage error is provided. This paper analyzes the effect of using periodic current references in a Lyapunov-based controlled boost DC/AC converter performing step-up inversion tasks. It is shown that, for sufficiently accurate current references, the system exhibits asymptotically stable periodic solutions with bounded error. Moreover, the paper propounds the use of Harmonic Balance (HB)-based techniques to obtain such current references. Simulation and experimental results confirm that this choice yields periodic output voltages with an error that may be lowered using higher HB approximations.Postprint (published version
Interpolation formula for the electrical conductivity of nonideal
  plasmas

On the basis of a quantum-statistical approach to the electrical conductivity
of nonideal plasmas we derive analytical results in the classical low-density
regime, in the degenerate Born limit, and for the contribution of the
Debye-Onsager relaxation effect. These explicit results are used to construct
an improved interpolation formula of the electrical conductivity valid in a
wide range of temperature and density which allows to compare with available
experimental data of nonideal plasmas.Comment: 7 pages, 1 tabl
Spectral line shape modeling and ion temperature fluctuations in tokamak
  edge plasmas

In this work, we use a passive advection model for ion temperature
fluctuations, in order to investigate their effects on Doppler Spectral line
shapes. The relevance of the model is discussed in the framework of the
Braginskii equations, and the subsequent Probability Density Function
evaluation relies on results obtained in neutral fluids. The resulting Doppler
line profiles are shown to exhibit characteristic exponential tails.Comment: 6 pages, 2 figures, to be published in Contributions to Plasma
  Physic
Optical properties and one-particle spectral function in non-ideal
  plasmas

A basic concept to calculate physical features of non-ideal plasmas, such as
optical properties, is the spectral function which is linked to the
self-energy. We calculate the spectral function for a non-relativistic hydrogen
plasma in $GW$-approximation. In order to go beyond $GW$ approximation, we
include self-energy and vertex correction to the polarization function in
lowest order. Partial compensation is observed. The relation of our approach to
$GW$ and $GW\Gamma$ calculations in other fields, such as the band-structure
calculations in semiconductor physics, is discussed. From the spectral function
we derive the absorption coefficient due to inverse bremsstrahlung via the
polarization function. As a result, a significant reduction of the absorption
as compared to the Bethe-Heitler formula for bremsstrahlung is obtained.Comment: 13 pages, 7 figures, 52 references. Submitted to Contrib. Plasma
  Phys. Results presented at the International Workshop on Physics of Non-ideal
  Plasmas (PNP12), Darmstadt, sept. 4.-8. 200
Hypernetted chain calculations for two-component plasmas

We have performed HNC calculations for dense beryllium plasma as studied
experimentally using x-ray Thomson scattering, recently. We treated
non-equilibrium situations with different electron and ion temperatures which
are relevant in pump-probe experiments on ultra-short time scales. To consider
quantum effects adequately, we used effective pair potentials to describe the
interactions. Results are compared with classical as well as quantum corrected
Debye model calculations.Comment: 7 pages, 4 figures. Contribution to the 12th International Workshop
  on the Physics of Non-Ideal Plasmas PNP 12, Sept. 4 - 8, 2006, Darmstadt,
  Germany. To appear in Contrib. Plasma Phy
Crystallization in mass-asymmetric electron-hole bilayers

We consider a \textit{mass-asymmetric} electron and hole bilayer. Electron
and hole Coulomb correlations and electron and hole quantum effects are treated
on first princles by path integral Monte Carlo methods. For a fixed layer
separation we vary the mass ratio $M$ of holes and electrons between 1 and 100
and analyze the structural changes in the system. While, for the chosen
density, the electrons are in a nearly homogeneous state, the hole arrangement
changes from homogeneous to localized, with increasing $M$ which is verified
for both, mesoscopic bilayers in a parabolic trap and for a macroscopic system.Comment: 10 pages, latex (styles files included
Equation of state for dense hydrogen and plasma phase transition

We calculate the equation of state of dense hydrogen within the chemical
picture. Fluid variational theory is generalized for a multi-component system
of molecules, atoms, electrons, and protons. Chemical equilibrium is supposed
for the reactions dissociation and ionization. We identify the region of
thermodynamic instability which is related to the plasma phase transition. The
reflectivity is calculated along the Hugoniot curve and compared with
experimental results. The equation-of-state data is used to calculate the
pressure and temperature profiles for the interior of Jupiter.Comment: 7 pages, 7 figures, contibution to the 12th International Workshop on
  the Physics of Non-Ideal Plasmas, Darmstadt, German
Properties of Dense Fluid Hydrogen and Helium in Giant Gas Planets

Equilibrium properties of hydrogen-helium mixtures under thermodynamic
conditions found in the interior of giant gas planets are studied by means of
density functional theory molecular dynamics simulations. Special emphasis is
placed on the molecular-to-atomic transition in the fluid phase of hydrogen in
the presence of helium. Helium has a substantial influence on the stability of
hydrogen molecules. The molecular bond is strengthened and its length is
shortened as a result of the increased localization of the electron charge
around the helium atoms, which leads to more stable hydrogen molecules compared
to pure hydrogen for the same thermodynamic conditions. The {\it ab initio}
treatment of the mixture enables us to investigate the structure of the liquid
and to discuss hydrogen-hydrogen, helium-helium, and hydrogen-helium
correlations on the basis of pair correlation functions.Comment: 6 pages, 3 figures, 1 table, proceedings PNP1
The level of non-thermal velocity fluctuations deduced from Doppler
  spectroscopy and its role on TJ-II confinement

The goal of this investigation is to study, in the line of previous works,
the level of velocity fluctuations in different scenarios of the TJ-II
stellarator. The method followed consists in measuring the apparent Doppler
temperature of C4+ and protons with high spectral resolution techniques with
spatial resolution. The level of turbulent velocities in the plasma has been
deduced from the difference observed between the apparent temperature of both
species, following a method previously presented and borrowed from
astrophysics. The study of this difference, as a function of plasma density and
injected power, provides a way to explore if this turbulence plays any role in
the confinement of the hot TJ-II plasma.Comment: 8 pages, 5 figure
Corrections to linear mixing in binary ionic mixtures and plasma
  screening at zero separation

Using the results of extensive Monte Carlo simulations we discuss corrections
to the linear mixing rule in strongly coupled binary ionic mixtures. We analyze
the plasma screening function at zero separation, H_{jk}(0), for two ions (of
types j=1,2 and k=1,2) in a strongly coupled binary mixture. The function
H_{jk}(0) is estimated by two methods: (1) from the difference of Helmholtz
Coulomb free energies at large and zero separations; (2) by fitting the Widom
expansion of H_{jk}(x) in powers of interionic distance x to Monte Carlo data
on the radial pair distribution function g_{jk}(x). These methods are shown to
be in good agreement. For illustration, we analyze the plasma screening
enhancement of nuclear burning rates in dense stellar matter.Comment: 4 pages, 2 figures, pre-peer reviewed version of the article accepted
  for publication in Contrib. Plasma Phys. (2009). The results can be applied
  to plasma screening enhancement of nuclear burning rates in dense stellar
  matte
Investigating transport of dust particles in plasmas

An algorithm has been developped, which makes it possible to automatically
extract trajectories of a large number of particles from fast imaging data,
allowing a statistical analysis of particles trajectories under various plasma
conditions, a better understanding of their influence on plasma properties, and
a better characterization of the plasma itself. In this contribution, we focus
on results obtained in a radiofrequency parallel plate reactor, where a large
amount of micron-sized carbon dust is produced in situ. The use of the rescaled
range analysis (R/S analysis) applied to dust particles displacements allows
decomposing dust dynamic on different time scales. It is shown that dust
displacement is dominated by collisions on short time scales whereas long term
behaviour is strongly influenced by large scale plasma fluctuations.Comment: This version contains 8 pages and 5 figures. This work has been
  presented in the 1st Int. Conf. on Plasma Diagnostics, O8, April 12-16 2010,
  Pont-\`a-Mousson, France (2010). It has been submitted to Contribution to
  Plasma Physic
Wave instabilities of a collisionless plasma in fluid approximation

Wave properties and instabilities in a magnetized, anisotropic,
collisionless, rarefied hot plasma in fluid approximation are studied, using
the 16-moments set of the transport equations obtained from the Vlasov
equations. These equations differ from the CGL-MHD fluid model (single fluid
equations by Chew, Goldberger, and Low, 1956) by including two anisotropic heat
flux evolution equations, where the fluxes invalidate the double polytropic CGL
laws. We derived the general dispersion relation for linear compressible wave
modes. Besides the classic incompressible fire hose modes there appear four
types of compressible wave modes: two fast and slow mirror modes - strongly
modified compared to the CGL model - and two thermal modes. In the presence of
initial heat fluxes along the magnetic field the wave properties become
different for the waves running forward and backward with respect to the
magnetic field. The well known discrepancies between the results of the CGL-MHD
fluid model and the kinetic theory are now removed: i) The mirror slow mode
instability criterion is now the same as that in the kinetic theory. ii)
Similarly, in kinetic studies there appear two kinds of fire hose instabilities
- incompressible and compressible ones. These two instabilities can arise for
the same plasma parameters, and the instability of the new compressible oblique
fire hose modes can become dominant. The compressible fire hose instability is
the result of the resonance coupling of three retrograde modes - two thermal
modes and a fast mirror mode. The results can be applied to the theory of solar
and stellar coronal and wind models.Comment: 18 pages, 11 figures, LaTeX, added explanations and references
  according to the referee's suggestions, fitted to the style of "Contributions
  to Plasma Physics" (now in press), corrections of some misprint
Shell Structure of Confined Charges at Strong Coupling

A theoretical description of shell structure for charged particles in a
harmonic trap is explored at strong coupling conditions of $\Gamma$ = 50 and
100. The theory is based on an extension of the hypernetted chain approximation
to confined systems plus a phenomenological representation of associated bridge
functions. Predictions are compared to corresponding Monte Carlo simulations
and quantitative agreement for the radial density profile is obtained.Comment: 9 pages, 5 figures. Presented at the 13th International Conference on
  the Physics of Non-Ideal Plasmas (PNP 13) held in Chernogolovka, Russia
  (September 13-18, 2009). Proceedings to be published in "Contributions to
  Plasma Physics" (Dec. 2009-Jan. 2010
Resistivity in warm dense plasmas beyond the average-atom model

The exploration of atomic properties of strongly coupled partially degenerate
plasmas, also referred to as warm dense matter, is important in astrophysics,
since this thermodynamic regime is encountered for instance in Jovian planets'
interior. One of the most important issues is the need for accurate equations
of state and transport coefficients. The Ziman formula has been widely used for
the computation of the static (DC) electrical resistivity. Usually, the
calculations are based on the continuum wavefunctions computed in the
temperature and density-dependent self-consistent potential of a fictive atom,
representing the average ionization state of the plasma (average-atom model).
We present calculations of the electrical resistivity of a plasma based on the
superconfiguration (SC) formalism. In this modeling, the contributions of all
the electronic configurations are taken into account. It is possible to obtain
all the situations between the two limiting cases: detailed configurations (a
super-orbital is a single orbital) and detailed ions (all orbitals are gathered
in the same super-orbital). The ingredients necessary for the calculation are
computed in a self-consistent manner for each SC, using a density-functional
description of the electrons. Electron exchange-correlation is handled in the
local-density approximation. The momentum transfer cross-sections are
calculated by using the phase shifts of the continuum electron wavefunctions
computed, in the potential of each SC, by the Schroedinger equation with
relativistic corrections (Pauli approximation). Comparisons with experimental
data are also presented.Comment: submitted to "Contributions to Plasma Physics
Thermodynamic functions of dense plasmas: analytic approximations for
  astrophysical applications

We briefly review analytic approximations of thermodynamic functions of fully
ionized nonideal electron-ion plasmas, applicable in a wide range of plasma
parameters, including the domains of nondegenerate and degenerate,
nonrelativistic and relativistic electrons, weakly and strongly coupled Coulomb
liquids, classical and quantum Coulomb crystals. We present improvements to
previously published approximations. Our code for calculation of thermodynamic
functions based on the reviewed approximations is made publicly available.Comment: 6 pages, 2 figures, Contributions to Plasma Physics, 2010, vol.50 (in
  press
Microfield Fluctuations and Spectral Line Shapes in Strongly Coupled
  Two-Component Plasmas

The spectral line shapes for hydrogen-like heavy ion emitters embedded in
strongly correlated two-component electron-ion plasmas are investigated with
numerical simulations. For that purpose the microfield fluctuations are
calculated by molecular dynamics simulations where short range quantum effects
are taken into account by using a regularized Coulomb potential for the
electron-ion interaction. The microfield fluctuations are used as input in a
numerical solution of the time-dependent Schroedinger equation for the
radiating electron. In distinction to the standard impact and quasistatic
approximations the method presented here allows to account for the correlations
between plasma ions and electrons. The shapes of the Ly-alpha line in Al are
investigated in the intermediate regime. The calculations are in good agreement
with experiments on the Ly-alpha line in laser generated plasmas.Comment: 5 figure
Long-range correlations of the surface charge density between electrical
  media with flat and spherical interfaces

We study the asymptotic long-range behavior of the time-dependent correlation
function of the surface charge density induced on the interface between two
media of distinct dielectric functions which are in thermal equilibrium with
one another as well as with the radiated electromagnetic field. We start with a
short review which summarizes the results obtained by using quantum and
classical descriptions of media, in both non-retarded and retarded regimes of
particle interactions. The classical static result for the flat interface is
rederived by using a combination of the microscopic linear response theory and
the macroscopic method of electrostatic image charges. The method is then
applied to the case of a spherically shaped interface between media.Comment: 6 pages, invited talk at the conference SCCS 2011, Budapes
Ab initio simulation of complex dielectric function for dense aluminum
  plasma

We present calculations of frequency-dependent complex dielectric function of
dense aluminum plasma by quantum molecular dynamics method for temperatures up
to 20 kK. Analysis shows that the dependencies for real and imaginary parts can
be interpolated by the Drude formula with two effective parameters: the mean
charge of ions and the effective frequency of collisions. The rise of these
parameters with temperature deviates from simple theoretical predictions.Comment: 4 pages, 5 figures, Proceedings of the conference "Strongly-Coupled
  Coulomb Systems - 2011
Electron screening effect on stellar thermonuclear fusion

We study the impact of plasma correlation effects on nonresonant
thermonuclear reactions for various stellar objects, namely in the liquid
envelopes of neutron stars, and the interiors of white dwarfs, low-mass stars,
and substellar objects. We examine in particular the effect of electron
screening on the enhancement of thermonuclear reactions in dense plasmas within
and beyond the linear mixing rule approximation as well as the corrections due
to quantum effects at high density. In addition, we examine some recent
unconventional (Yukawa-potential and "quantum-tail") theoretical results on
stellar thermonuclear fusions and show that these scenarios do not apply to
stellar conditions.Comment: 9 pages, 4 figures; Proceedings of the 14th International Conference
  on Physics of Nonideal Plasmas "PNP-14" (9-14 September 2012, Rostock,
  Germany
Dynamics of Hubbard nano-clusters following strong excitation

The Hubbard model is a prototype for strongly correlated electrons in
condensed matter, for molecules and fermions or bosons in optical lattices.
While the equilibrium properties of these systems have been studied in detail,
the excitation and relaxation dynamics following a perturbation of the system
are only poorly explored. Here, we present results for the dynamics of
electrons following nonlinear strong excitation that are based on a
nonequilibrium Green functions approach. We focus on small systems---"Hubbard
nano-clusters"---that contain just a few particles where, in addition to the
correlation effects, finite size effects and spatial inhomegeneity can be
studied systematically
A critique of recent semi-classical spin-half quantum plasma theories

Certain recent semi-classical theories of spin-half quantum plasmas are
examined with regard to their internal consistency, physical applicability and
relevance to fusion, astrophysical and condensed matter plasmas. It is shown
that the derivations and some of the results obtained in these theories are
internally inconsistent and contradict well-established principles of quantum
and statistical mechanics, especially in their treatment of fermions and spin.
Claims of large semi-classical effects of spin magnetic moments that could
dominate the plasma dynamics are found to be invalid both for single-particles
and collectively. Larmor moments dominate at high temperature while spin
moments cancel due to Pauli blocking at low temperatures. Explicit numerical
estimates from a variety of plasmas are provided to demonstrate that spin
effects are indeed much smaller than many neglected classical effects. The
analysis presented suggests that the aforementioned `Spin Quantum Hydrodynamic'
theories are not relevant to conventional laboratory or astrophysical plasmas.Comment: 11 pages, To appear in Contributions to Plasma Physics. Minor
  correction on page 3 to electron spin magnetic momen
Thermodynamics of the quark-gluon plasma at finite chemical potential:
  color path integral Monte Carlo results

Based on the constituent quasiparticle model of the quark-gluon plasma (QGP),
color quantum path-integral Monte-Carlo (PIMC) calculations of the
thermodynamic properties of the QGP are performed. We extend our previous zero
chemical potential simulations to the QGP at finite baryon chemical potential.
The results indicate that color PIMC can be applied not only above the QCD
critical temperature $T_c$ but also below $T_c$. Besides reproducing the
lattice equation of state our approach yields also valuable additional insight
into the internal structure of the QGP, via the pair distribution functions of
the various quasiparticles. In particular, the pair distribution function of
gluons reflects the existence of gluon-gluon bound states at low temperatures
and $\mu=175$ MeV, i.e. glueballs, while meson-like bound states are not found
Toward a Nonequilibrium Green functions approach to diffusion in
  strongly coupled finite quantum systems

Transport properties of strongly correlated quantum systems are of central
interest in condensed matter, ultracold atoms and in dense plasmas. There, the
proper treatment of strong correlations poses a great challenge to theory.
Here, we apply a Nonequilibrium Green Functions approach using a lattice model
as a basic system. This allow us to treat a finite spatially inhomogeneous
system with an arbitrary nonequilibrium initial state. Placing all particles
initially to one side of the system allows for a nonequilibrium study of
diffusion. Strong correlation effects are incorporated via T-matrix
selfenergies