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2024-03-13
Effects of wave damping and finite perpendicular scale on three-dimensional Alfvén wave parametric decay in low-beta plasmas
Shear Alfven wave parametric decay instability (PDI) provides a potential path toward significant wave dissipation and plasma heating. However, fundamental questions regarding how PDI is excited in a realistic three-dimensional (3D) open system and how critically the finite perpendicular wave scale -- as found in both ...
2403.08179v1
2024-03-19
Polarization Dynamics in Paramagnet of Charged Quark-Gluon Plasma
It is commonly understood that the strong magnetic field produced in heavy ion collisions is short-lived. The electric conductivity of the quark-gluon plasma is unable to significantly extend the life time of magnetic field. We propose an alternative scenario to achieve this: with finite baryon density and spin polariz...
2403.12615v1
2024-03-25
Radiation damping of a Rayleigh scatterer illuminated by a plane wave
We investigate the radiation damping experienced by a dielectric spherical particle when it is illuminated by an electromagnetic plane wave within the Rayleigh regime. We derive the equivalent electric dipole of the moving particle and subsequently calculate the electromagnetic force acting on it from two different app...
2403.16618v1
2006-04-14
The UCSD Radio-Selected Quasar Survey for Damped Lyman alpha System
As large optical quasar surveys for damped Lya become a reality and the study of star forming gas in the early Universe achieves statistical robustness, it is now vital to identify and quantify the sources of systematic error. Because the nature of optically-selected quasar surveys makes them vulnerable to dust obscura...
0604334v1
2012-04-12
Evidence of Gunn-Peterson damping wings in high-z quasar spectra: strengthening the case for incomplete reionization
The spectra of several high-redshift (z>6) quasars have shown evidence for a Gunn-Peterson (GP) damping wing, indicating a substantial mean neutral hydrogen fraction (x_HI > 0.03) in the z ~ 6 intergalactic medium (IGM). However, previous analyses assumed that the IGM was uniformly ionized outside of the quasar's HII r...
1204.2838v2
2013-05-31
Highly inclined and eccentric massive planets I: Planet-disc interactions
In the Solar System, planets have a small inclination with respect to the equatorial plane of the Sun, but there is evidence that in extrasolar systems the inclination can be very high. This spin-orbit misalignment is unexpected, as planets form in a protoplanetary disc supposedly aligned with the stellar spin. Planet-...
1305.7330v1
2014-10-20
Frequency-dependent attenuation and elasticity in unconsolidated earth materials: effect of damping
We use the Discrete Element Method (DEM) to understand the underlying attenuation mechanism in granular media, with special applicability to the measurements of the so-called effective mass developed earlier. We consider that the particles interact via Hertz-Mindlin elastic contact forces and that the damping is descri...
1410.5484v2
2020-08-05
Fast optimization via inertial dynamics with closed-loop damping
In a Hilbert space $H$, in order to develop fast optimization methods, we analyze the asymptotic behavior, as time $t$ tends to infinity, of inertial continuous dynamics where the damping acts as a closed-loop control. The function $f: H \to R$ to be minimized (not necessarily convex) enters the dynamic through it grad...
2008.02261v3
2023-01-10
Cosmic Ray Drag and Damping of Compressive Turbulence
While it is well-known that cosmic rays (CRs) can gain energy from turbulence via second order Fermi acceleration, how this energy transfer affects the turbulent cascade remains largely unexplored. Here, we show that damping and steepening of the compressive turbulent power spectrum are expected once the damping time $...
2301.04156v2
2024-02-12
Relaxation of weakly collisional plasma: continuous spectra, Landau eigenmodes, and transition from the collisionless to the fluid limit
The relaxation of a weakly collisional plasma is described by the Boltzmann-Poisson equations with the Lenard-Bernstein collision operator. We perform a perturbative analysis of these equations, and obtain, for the first time, exact analytic solutions, enabling definitive resolutions to long-standing controversies rega...
2402.07992v1
1995-09-21
Damped Lyman-alpha and Lyman Limit Absorbers in the Cold Dark Matter Model
We study the formation of damped \lya and Lyman limit absorbers in a hierarchical clustering scenario using a gas dynamical simulation of an $\Omega = 1$, cold dark matter universe. In the simulation, these high column density systems are associated with forming galaxies. Damped \lya absorption, $N_{HI} \simgt 10^{20.2...
9509106v1
1995-09-21
Nonlinear Damping of Oscillations in Tidal-Capture Binaries
We calculate the damping of quadrupole f and low order g modes (primary modes) by nonlinear coupling to other modes of the star. This damping is orders of magnitude more rapid than direct radiative damping when the primary amplitude is large, as in tidal capture. Primary modes destabilize high degree g-modes of half ...
9509112v1
1997-08-12
Spectroscopy of PKS 0528-260: New Limits on CO Absorption and Emission
We have obtained a moderate resolution spectrum of the quasar PKS 0528-250 with the Red Channel Spectrograph on the Multiple Mirror Telescope (MMT) in order to study a damped Lyman alpha absorption line system at z = 2.8115. We obtain a new upper limit for the CO column density for the z = 2.8108 velocity component i...
9708104v1
1998-11-04
GMRT Observations of Low z Damped Lyman-alpha Absorbers
We present Giant Metrewave Radio Telescope (GMRT) observations of redshifted HI 21cm absorption in two low redshift (z=0.2212, z=0.0912) damped Lyman-alpha systems seen towards the gigahertz peaked source OI 363 (z_em = 0.630). The object at z=0.0912 is the lowest redshift damped Lyman-alpha system known to date. Groun...
9811068v1
2002-01-25
Galaxies Associated with z~4 Damped Lya Systems: I. Imaging and Photometric Selection
This paper describes the acquisition and analysis of imaging data for the identification of galaxies associated with z~4 damped Lya systems. We present deep BRI images of three fields known to contain four z~4 damped systems. We discuss the reduction and calibration of the data, detail the color criteria used to identi...
0201417v2
2002-02-25
Eccentricity Evolution for Planets in Gaseous Disks
We investigate the hypothesis that interactions between a giant planet and the disk from which it forms promote eccentricity growth. These interactions are concentrated at discrete Lindblad and corotation resonances. Interactions at principal Lindblad resonances cause the planet's orbit to migrate and open a gap in the...
0202462v1
2003-07-23
Dusty Molecular Cloud Collapse in the Presence of Alfvén Waves
It has been shown that magnetic fields play an important role in the stability of molecular clouds, mainly perpendicularly to the field direction. However, in the parallel direction the stability is a serious problem still to be explained. Interstellar turbulence may allow the generation of Alfv\'en waves that propagat...
0307411v1
2005-02-28
Thermal Evolution of a Pulsating Neutron Star
We have derived a set of equations to describe the thermal evolution of a neutron star which undergoes small-amplitude radial pulsations. We have taken into account, in the frame of the General Theory of Relativity, the pulsation damping due to the bulk and shear viscosity and the accompanying heating of the star. The ...
0502583v2
2005-05-02
Collisionless Damping of Fast MHD Waves in Magneto-rotational Winds
We propose collisionless damping of fast MHD waves as an important mechanism for the heating and acceleration of winds from rotating stars. Stellar rotation causes magnetic field lines anchored at the surface to form a spiral pattern and magneto-rotational winds can be driven. If the structure is a magnetically dominat...
0505013v5
2006-08-05
The nature of damped Lyman alpha and sub-damped Lyman alpha absorbers
We present arguments based on the measured abundances in individual damped Lyman alpha systems (DLAs) and sub-damped Lyman alpha systems (sub-DLAs), and also the average abundances inferred in large samples of QSO absorption line systems, to suggest that the amount of dust in intervening QSO absorbers is small and is n...
0608127v2
2007-02-12
The Ucsd/Keck Damped Lya Abundance Database: A Decade of High Resolution Spectroscopy
We publish the Keck/HIRES and Keck/ESI spectra that we have obtained during the first 10 years of Keck observatory operations. Our full sample includes 42 HIRES spectra and 39 ESI spectra along 65 unique sightlines providing abundance measurements on ~85 damped Lya systems. The normalized data can be downloaded from th...
0702325v1
1998-06-30
Structure and Spin Dynamics of La$_{0.85}$Sr$_{0.15}$MnO$_3$
Neutron scattering has been used to study the structure and spin dynamics of La$_{0.85}$Sr$_{0.15}$MnO$_3$. The magnetic structure of this system is ferromagnetic below T_C = 235 K. We see anomalies in the Bragg peak intensities and new superlattice peaks consistent with the onset of a spin-canted phase below T_{CA} = ...
9806381v1
1999-02-01
Damping Rates and Mean Free Paths of Soft Fermion Collective Excitations in a Hot Fermion-Gauge-Scalar Theory
We study the transport coefficients, damping rates and mean free paths of soft fermion collective excitations in a hot fermion-gauge-scalar plasma with the goal of understanding the main physical mechanisms that determine transport of chirality in scenarios of non-local electroweak baryogenesis. The focus is on identif...
9902218v2
2002-08-29
Some notes on ideology of waves in plasmas
Our last three papers provide an occasion to make some brief notes on ideology of waves in plasmas and to rehabilitate Vlasov prescription to calculate relevant logarithmically divergent integrals in the principal value sense. In this approach asymptotical solutions of plasma oscillations are selected according to self...
0208098v7
2004-11-26
Open quantum systems
The damping of the harmonic oscillator is studied in the framework of the Lindblad theory for open quantum systems. A generalization of the fundamental constraints on quantum mechanical diffusion coefficients which appear in the master equation for the damped quantum oscillator is presented; the Schr\"odinger, Heisenbe...
0411189v1
2006-02-17
Damped quantum harmonic oscillator
In the framework of the Lindblad theory for open quantum systems the damping of the harmonic oscillator is studied. A generalization of the fundamental constraints on quantum mechanical diffusion coefficients which appear in the master equation for the damped quantum oscillator is presented; the Schr\"odinger and Heise...
0602149v1
2007-04-12
The effect of the solar corona on the attenuation of small-amplitude prominence oscillations. I. Longitudinal magnetic field
Context. One of the typical features shown by observations of solar prominence oscillations is that they are damped in time and that the values of the damping times are usually between one and three times the corresponding oscillatory period. However, the mechanism responsible for the attenuation is still not well-know...
0704.1566v2
2007-10-01
Lyman-alpha Damping Wing Constraints on Inhomogeneous Reionization
One well-known way to constrain the hydrogen neutral fraction, x_H, of the high-redshift intergalactic medium (IGM) is through the shape of the red damping wing of the Lya absorption line. We examine this method's effectiveness in light of recent models showing that the IGM neutral fraction is highly inhomogeneous on l...
0710.0371v1
2008-02-11
Eccentricity of masing disks in Active Galactic Nuclei
Observations of Keplerian disks of masers in NCG 4258 and other Seyfert galaxies can be used to obtain geometric distance estimates and derive the Hubble constant. The ultimate precision of such measurements could be limited by uncertainties in the disk geometry. Using a time-dependent linear theory model, we study the...
0802.1524v1
2008-02-20
The Effect of Charon's Tidal Damping on the Orbits of Pluto's Three Moons
Pluto's recently discovered minor moons, Nix and Hydra, have almost circular orbits, and are nearly coplanar with Charon, Pluto's major moon. This is surprising because tidal interactions with Pluto are too weak to damp their eccentricities. We consider an alternative possibility: that Nix and Hydra circularize their o...
0802.2939v1
2008-03-18
Non-adiabatic magnetohydrodynamic waves in a cylindrical prominence thread with mass flow
High-resolution observations show that oscillations and waves in prominence threads are common and that they are attenuated in a few periods. In addition, observers have also reported the presence of material flows in such prominence fine-structures. Here we investigate the time damping of non-leaky oscillations suppor...
0803.2600v2
2008-07-28
Thermal fluctuations in moderately damped Josephson junctions: Multiple escape and retrapping, switching- and return-current distributions and hysteresis
A crossover at a temperature T* in the temperature dependence of the width s of the distribution of switching currents of moderately damped Josephson junctions has been reported in a number of recent publications, with positive ds/dT and IV characteristics associated with underdamped behaviour for lower temperatures T<...
0807.4502v1
2009-02-26
Viscous propagation of mass flow variability in accretion discs
We study mass flow rate through a disc resulting from a varying mass supply rate. Variable mass supply rate occurs, e.g., during disc state transitions, and in interacting eccentric binaries. It is, however, damped by the viscosity of the disc. Here, we calculate this damping in detail. We derive an analytical descript...
0902.4530v2
2010-04-09
Oscillations of weakly viscous conducting liquid drops in a strong magnetic field
We analyse small-amplitude oscillations of a weakly viscous electrically conducting liquid drop in a strong uniform DC magnetic field. An asymptotic solution is obtained showing that the magnetic field does not affect the shape eigenmodes, which remain the spherical harmonics as in the non-magnetic case. Strong magneti...
1004.1548v2
2011-02-03
Damping of Electron Density Structures and Implications for Interstellar Scintillation
The forms of electron density structures in kinetic Alfven wave turbulence are studied in connection with scintillation. The focus is on small scales $L \sim 10^8-10^{10}$ cm where the Kinetic Alfv\'en wave (KAW) regime is active in the interstellar medium. MHD turbulence converts to a KAW cascade, starting at 10 times...
1102.0810v2
2011-09-28
Different dimensionality trends in the Landau damping of magnons in iron, cobalt and nickel: time dependent density functional study
We study the Landau damping of ferromagnetic magnons in Fe, Co, and Ni as the dimensionality of the system is reduced from three to two. We resort to the \textit{ab initio} linear response time dependent density functional theory in the adiabatic local spin density approximation. The numerical scheme is based on the Ko...
1109.6217v2
2011-10-06
Dissipative and conservative nonlinearity in carbon nanotube and graphene mechanical resonators
Graphene and carbon nanotubes represent the ultimate size limit of one and two-dimensional nanoelectromechanical resonators. Because of their reduced dimensionality, graphene and carbon nanotubes display unusual mechanical behavior; in particular, their dynamics is highly nonlinear. Here, we review several types of non...
1110.1234v1
2012-06-02
Slow Mode Oscillations and Damping of Hot Solar Coronal Loops
The effect of temperature inhomogeneity on the periods, their ratios (fundamental vs. first overtone), and the damping times of the standing slow modes in gravitationally stratified solar coronal loops are studied. The effects of optically thin radiation, compressive viscosity, and thermal conduction are considered. Th...
1206.0366v1
2012-09-15
Damped kink oscillations of flowing prominence threads
Transverse oscillations of thin threads in solar prominences are frequently reported in high-resolution observations. Two typical features of the observations are that the oscillations are damped in time and that simultaneous mass flows along the threads are detected. Flows cause the dense threads to move along the pro...
1209.3382v1
2013-04-13
Parametric survey of longitudinal prominence oscillation simulations
It is found that both microflare-sized impulsive heating at one leg of the loop and a suddenly imposed velocity perturbation can propel the prominence to oscillate along the magnetic dip. An extensive parameter survey results in a scaling law, showing that the period of the oscillation, which weakly depends on the leng...
1304.3798v1
2013-06-08
Observation of a Berry phase anti-damping spin-orbit torque
Recent observations of current-induced magnetization switching at ferromagnet/normal-conductor interfaces have important consequences for future magnetic memory technology. In one interpretation, the switching originates from carriers with spin-dependent scattering giving rise to a relativistic anti-damping spin-orbit ...
1306.1893v1
2013-08-20
Stringent constraints on the H I spin temperature in two z > 3 Damped Lyman-alpha systems from redshifted 21 cm absorption studies
Physical properties of Damped Lyman-alpha absorbers and their evolution are closely related to galaxy formation and evolution theories, and have important cosmological implications. H I 21 cm absorption study is one useful way of measuring the temperature of these systems. In this work, very strong constraints on the t...
1308.4410v1
2013-09-26
Non-Landau damping of magnetic excitations in systems with localized and itinerant electrons
We discuss the form of the damping of magnetic excitations in a metal near a ferromagnetic instability. The paramagnon theory predicts that the damping term should have the form $\Omega/\Gamma (q)$ with $\Gamma (q) \propto q$ (the Landau damping). However, the experiments on uranium metallic compounds UGe$_2$ and UCoGe...
1309.7065v3
2014-06-16
Design of the Readout Electronics for the Qualification Model of DAMPE BGO Calorimeter
The DAMPE (DArk Matter Particle Explorer) is a scientific satellite being developed in China, aimed at cosmic ray study, gamma ray astronomy, and searching for the clue of dark matter particles, with a planned mission period of more than 3 years and an orbit altitude of about 500 km. The BGO Calorimeter, which consists...
1406.3886v1
2014-11-24
Damping of liquid sloshing by foams
When a container is set in motion, the free surface of the liquid starts to oscillate or slosh. Such effects can be observed when a glass of water is handled carelessly and the fluid sloshes or even spills over the rims of the container. However, beer does not slosh as readily as water, which suggests that foam could b...
1411.6542v2
2015-04-16
Attenuation of short strongly nonlinear stress pulses in dissipative granular chains
Attenuation of short, strongly nonlinear stress pulses in chains of spheres and cylinders was investigated experimentally and numerically for two ratios of their masses keeping their contacts identical. The chain with mass ratio 0.98 supports solitary waves and another one (with mass ratio 0.55) supports nonstationary ...
1504.04344v1
2015-04-17
Chiral damping of magnetic domain walls
Structural symmetry breaking in magnetic materials is responsible for a variety of outstanding physical phenomena. Examples range from the existence of multiferroics, to current induced spin orbit torques (SOT) and the formation of topological magnetic structures. In this letter we bring into light a novel effect of th...
1504.04411v1
2015-07-28
Spatial damping of propagating sausage waves in coronal cylinders
Sausage modes are important in coronal seismology. Spatially damped propagating sausage waves were recently observed in the solar atmosphere. We examine how wave leakage influences the spatial damping of sausage waves propagating along coronal structures modeled by a cylindrical density enhancement embedded in a unifor...
1507.07724v1
2015-10-19
On the branching of the quasinormal resonances of near-extremal Kerr black holes
It has recently been shown by Yang. et. al. [Phys. Rev. D {\bf 87}, 041502(R) (2013)] that rotating Kerr black holes are characterized by two distinct sets of quasinormal resonances. These two families of quasinormal resonances display qualitatively different asymptotic behaviors in the extremal ($a/M\to 1$) black-hole...
1510.05604v1
2016-02-16
Damping and power spectra of quasi-periodic intensity disturbances above a solar polar coronal hole
We study intensity disturbances above a solar polar coronal hole seen in the AIA 171 \AA\ and 193 \AA\ passbands, aiming to provide more insights into their physical nature. The damping and power spectra of the intensity disturbances with frequencies from 0.07 mHz to 10.5 mHz are investigated. The damping of the intens...
1602.04883v1
2016-04-20
Nonlinear wave damping due to multi-plasmon resonances
For short wavelengths, it is well known that the linearized Wigner-Moyal equation predicts wave damping due to wave-particle interaction, where the resonant velocity shifted from the phase velocity by a velocity $v_q = \hbar k/2m$. Here $\hbar$ is the reduced Planck constant, $k$ is the wavenumber and $m$ is the electr...
1604.05983v2
2016-05-09
Storage-ring Electron Cooler for Relativistic Ion Beams
Application of electron cooling at ion energies above a few GeV has been limited due to reduction of electron cooling efficiency with energy and difficulty in producing and accelerating a high-current high-quality electron beam. A high-current storage-ring electron cooler offers a solution to both of these problems by ...
1605.02594v1
2016-07-06
Measuring Collisionless Damping in Heliospheric Plasmas using Field-Particle Correlations
An innovative field-particle correlation technique is proposed that uses single-point measurements of the electromagnetic fields and particle velocity distribution functions to investigate the net transfer of energy from fields to particles associated with the collisionless damping of turbulent fluctuations in weakly c...
1607.01738v1
2016-07-22
Excitation of nonlinear ion acoustic waves in CH plasmas
Excitation of nonlinear ion acoustic wave (IAW) by an external electric field is demonstrated by Vlasov simulation. The frequency calculated by the dispersion relation with no damping is verified much closer to the resonance frequency of the small-amplitude nonlinear IAW than that calculated by the linear dispersion re...
1607.06598v1
2016-11-17
A stable partitioned FSI algorithm for rigid bodies and incompressible flow. Part II: General formulation
A stable partitioned algorithm is developed for fluid-structure interaction (FSI) problems involving viscous incompressible flow and rigid bodies. This {\em added-mass partitioned} (AMP) algorithm remains stable, without sub-iterations, for light and even zero mass rigid bodies when added-mass and viscous added-damping...
1611.05703v2
2017-03-01
The Plastic Scintillator Detector at DAMPE
he DArk Matter Particle Explorer (DAMPE) is a general purposed satellite-borne high energy $\gamma-$ray and cosmic ray detector, and among the scientific objectives of DAMPE are the searches for the origin of cosmic rays and an understanding of Dark Matter particles. As one of the four detectors in DAMPE, the Plastic S...
1703.00098v1
2017-03-22
Observation of a strong coupling effect on electron-ion collisions in ultracold plasmas
Ultracold plasmas (UCP) provide a well-controlled system for studying multiple aspects in plasma physics that include collisions and strong coupling effects. By applying a short electric field pulse to a UCP, a plasma electron center-of-mass (CM) oscillation can be initiated. In accessible parameter ranges, the damping...
1703.07852v2
2017-04-18
Critical pairing fluctuations in the normal state of a superconductor: pseudogap and quasi-particle damping
We study the effect of critical pairing fluctuations on the electronic properties in the normal state of a clean superconductor in three dimensions. Using a functional renormalization group approach to take the non-Gaussian nature of critical fluctuations into account, we show microscopically that in the BCS regime, wh...
1704.05282v2
2017-05-29
Probing decoherence in plasmonic waveguides in the quantum regime
We experimentally investigate the decoherence of single surface plasmon polaritons in metal stripe waveguides. In our study we use a Mach-Zehnder configuration previously considered for measuring decoherence in atomic, electronic and photonic systems. By placing waveguides of different length in one arm we are able to ...
1705.10344v2
2017-07-21
Spatially Localized Particle Energization by Landau Damping in Current Sheets Produced by Strong Alfven Wave Collisions
Understanding the removal of energy from turbulent fluctuations in a magnetized plasma and the consequent energization of the constituent plasma particles is a major goal of heliophysics and astrophysics. Previous work has shown that nonlinear interactions among counterpropagating Alfven waves---or Alfven wave collisio...
1708.00757v1
2017-10-30
Enhancement of intrinsic magnetic damping in defect-free epitaxial Fe3O4 thin films
We have investigated the magnetic damping of precessional spin dynamics in defect-controlled epitaxial grown Fe$_3$O$_4$(111)/Yttria-stabilized Zirconia (YSZ) nanoscale films by all-optical pump-probe measurements. The intrinsic damping constant of the defect-free Fe$_3$O$_4$ film is found to be strikingly larger than ...
1710.10938v2
2018-05-26
Critical collapse of ultra-relativistic fluids: damping or growth of aspherical deformations
We perform fully nonlinear numerical simulations to study aspherical deformations of the critical self-similar solution in the gravitational collapse of ultra-relativistic fluids. Adopting a perturbative calculation, Gundlach predicted that these perturbations behave like damped or growing oscillations, with the freque...
1805.10442v1
2018-06-19
Non-linear Relaxation of Interacting Bosons Coherently Driven on a Narrow Optical Transition
We study the dynamics of a two-component Bose-Einstein condensate (BEC) of $^{174}$Yb atoms coherently driven on a narrow optical transition. The excitation transfers the BEC to a superposition of states with different internal and momentum quantum numbers. We observe a crossover with decreasing driving strength betwee...
1806.07210v2
2018-10-16
The Solution to the Differential Equation with Linear Damping describing a Physical Systems governed by a Cubic Energy Potential
An analytical solution to the nonlinear differential equation describing the equation of motion of a particle moving in an unforced physical system with linear damping, governed by a cubic potential well, is presented in terms of the Jacobi elliptic functions. In the attractive region of the potential the system become...
1810.10336v1
2019-01-10
Damping and softening of transverse acoustic phonons in colossal magnetoresistive La$_{0.7}$Ca$_{0.3}$MnO$_3$ and La$_{0.7}$Sr$_{0.3}$MnO$_3$
Neutron spectroscopy is used to probe transverse acoustic phonons near the (2, 2, 0) Bragg position in colossal magnetoresistive La0.7Ca0.3MnO3 and La0.7Sr0.3MnO3. Upon warming to temperatures near Tc = 257 K the phonon peaks in La0.7Ca0.3MnO3 soften and damp significantly with the phonon half width at half maximum app...
1901.03394v1
2019-03-13
Inference of magnetic field strength and density from damped transverse coronal waves
A classic application of coronal seismology uses transverse oscillations of waveguides to obtain estimates of the magnetic field strength. The procedure requires information on the density of the structures. Often, it ignores the damping of the oscillations. We computed marginal posteriors for parameters such as the wa...
1903.05437v1
2019-03-14
A metal-poor damped Ly-alpha system at redshift 6.4
We identify a strong Ly-alpha damping wing profile in the spectrum of the quasar P183+05 at z=6.4386. Given the detection of several narrow metal absorption lines at z=6.40392, the most likely explanation for the absorption profile is that it is due to a damped Ly-alpha system. However, in order to match the data a con...
1903.06186v2
2019-04-30
DmpIRFs and DmpST: DAMPE Instrument Response Functions and Science Tools for Gamma-Ray Data Analysis
GeV gamma ray is an important observation target of DArk Matter Particle Explorer (DAMPE) for indirect dark matter searching and high energy astrophysics. We present in this work a set of accurate instrument response functions of DAMPE (DmpIRFs) including the effective area, point-spread function and energy dispersion ...
1904.13098v1
2019-05-14
Fractional damping through restricted calculus of variations
We deliver a novel approach towards the variational description of Lagrangian mechanical systems subject to fractional damping by establishing a restricted Hamilton's principle. Fractional damping is a particular instance of non-local (in time) damping, which is ubiquitous in mechanical engineering applications. The re...
1905.05608v1
2019-05-22
Ultra-low magnetic damping in Co 2 Mn-based Heusler compounds: promising materials for spintronic
The prediction of ultra-low magnetic damping in Co 2 MnZ Heusler half-metal thin-film magnets is explored in this study and the damping response is shown to be linked to the underlying electronic properties. By substituting the Z elements in high crystalline quality films (Co 2 MnZ with Z=Si, Ge, Sn, Al, Ga, Sb), elect...
1905.08987v1
2019-07-16
Damping of slow magnetoacoustic oscillations by the misbalance between heating and cooling processes in the solar corona
Rapidly decaying slow magnetoacoustic waves are regularly observed in the solar coronal structures, offering a promising tool for a seismological diagnostics of the coronal plasma, including its thermodynamical properties. The effect of damping of standing slow magnetoacoustic oscillations in the solar coronal loops is...
1907.07051v1
2019-07-29
Breather arrest in a chain of damped oscillators with Hertzian contact
We explore breather propagation in the damped oscillatory chain with essentially nonlinear (non-linearizable) nearest-neighbour coupling. Combination of the damping and the substantially nonlinear coupling leads to rather unusual two-stage pattern of the breather propagation. The first stage occurs at finite fragment o...
1907.12462v1
2019-08-22
Influence of structure and cation distribution on magnetic anisotropy and damping in Zn/Al doped nickel ferrites
An in-depth analysis of Zn/Al doped nickel ferrites grown by reactive magnetron sputtering is relevant due to their promising characteristics for applications in spintronics. The material is insulating and ferromagnetic at room temperature with an additional low magnetic damping. By studying the complex interplay betwe...
1908.08257v3
2019-09-11
Critical corrections to formulations of nonlinear energy dissipation of ultrasonically excited bubbles and a unifying parameter to asses and enhance bubble activity in applications
Nonlinear oscillations of bubbles can significantly increase the attenuation of the host media. Optimization of bubble related applications needs a realistic estimation of the medium attenuation and bubble activity. A correct estimation of the wave attenuation in bubbly media requires an accurate estimation of the powe...
1909.04864v1
2019-09-14
Measurement-Based Wide-Area Damping of Inter-Area Oscillations based on MIMO Identification
Interconnected power grid exhibits oscillatory response after a disturbance in the system. One such type of oscillations, the inter-area oscillations has the oscillation frequency in the range of 0.1 to 1 Hz. The damping of inter-area oscillations is difficult with local controllers, but it can be achieved using a Wide...
1909.06687v1
2019-12-09
Analytical solution of linearized equations of the Morris-Lecar neuron model at large constant stimulation
The classical biophysical Morris-Lecar model of neuronal excitability predicts that upon stimulation of the neuron with a sufficiently large constant depolarizing current there exists a finite interval of the current values where periodic spike generation occurs. Above the upper boundary of this interval, there is four...
1912.04083v4
2020-03-16
Spin-orbit torques originating from bulk and interface in Pt-based structures
We investigated spin-orbit torques in prototypical Pt-based spintronic devices. We found that, in Pt/Ni and Pt/Fe bilayers, the damping-like torque efficiency depends on the thickness of the Pt layer. We also found that the damping-like torque efficiency is almost identical in the Pt/Ni and Pt/Fe bilayers despite the s...
2003.07271v2
2020-03-23
Heat-like and wave-like lifespan estimates for solutions of semilinear damped wave equations via a Kato's type lemma
In this paper we study several semilinear damped wave equations with "subcritical" nonlinearities, focusing on demonstrating lifespan estimates for energy solutions. Our main concern is on equations with scale-invariant damping and mass. Under different assumptions imposed on the initial data, lifespan estimates from a...
2003.10578v1
2020-09-03
Dynamics of magnetic collective modes in the square and triangular lattice Mott insulators at finite temperature
We study the equilibrium dynamics of magnetic moments in the Mott insulating phase of the Hubbard model on the square and triangular lattice. We rewrite the Hubbard interaction in terms of an auxiliary vector field and use a recently developed Langevin scheme to study its dynamics. A thermal `noise', derivable approxim...
2009.01833v2
2020-09-15
Classification of the mechanisms of wave energy dissipation in the nonlinear oscillations of coated and uncoated bubbles
Acoustic waves are dissipated when they pass through bubbly media. Dissipation by bubbles takes place through thermal damping (Td), radiation damping (Rd) and damping due to the friction of the liquid (Ld) and friction of the coating (Cd). Knowledge of the contributions of the Td, Rd, Ld and Cd during nonlinear bubble ...
2009.07380v1
2020-11-18
The effect of redshift degeneracy and the damping effect of viscous medium on the information extracted from gravitational wave signals
Considering the cosmological redshift $z_c$ , the mass of GW source extracted from GW signal is $1+z_c$ times larger than its intrinsic value, and distance between detector and GW source should be regarded as luminosity distance. However, besides cosmological redshift, there are other kinds of redshifts should be consi...
2011.09169v2
2020-12-28
On the Efficacy of Friction Damping in the Presence of Nonlinear Modal Interactions
This work addresses friction-induced modal interactions in jointed structures, and their effects on the passive mitigation of vibrations by means of friction damping. Under the condition of (nearly) commensurable natural frequencies, the nonlinear character of friction can cause so-called nonlinear modal interactions. ...
2101.03232v1
2021-06-30
Origin of Nonlinear Damping due to Mode Coupling in Auto-Oscillatory Modes Strongly Driven by Spin-Orbit Torque
We investigate the physical origin of nonlinear damping due to mode coupling between several auto-oscillatory modes driven by spin-orbit torque in constricted Py/Pt heterostructures by examining the dependence of auto-oscillation on temperature and applied field orientation. We observe a transition in the nonlinear dam...
2107.00150v2
2021-07-15
On the long-time behavior for a damped Navier-Stokes-Bardina model
In this paper, we consider a damped Navier-Stokes-Bardina model posed on the whole three-dimensional. These equations have an important physical motivation and they arise from some oceanic model. From the mathematical point of view, they write down as the well-know Navier-Stokes equations with an additional nonlocal op...
2107.07070v2
2021-07-17
Plasmon-Exciton Coupling Effect on Plasmon Damping
Plasmon decay via the surface or interface is a critical process for practical energy conversion and plasmonic catalysis. However, the relationship between plasmon damping and the coupling between the plasmon and 2D materials is still unclear. The spectral splitting due to plasmon-exciton interaction impedes the conven...
2107.08230v1
2021-10-12
Outflows in the presence of cosmic rays and waves with cooling
Plasma outflow from a gravitational potential well with cosmic rays and self-excited Alfv\'en waves with cooling and wave damping is studied in the hydrodynamics regime. We study outflows in the presence of cosmic ray and Alfv\'en waves including the effect of cooling and wave damping. We seek physically allowable stea...
2110.06170v1
2021-11-19
Finite time extinction for a class of damped Schr{ö}dinger equations with a singular saturated nonlinearity
We present some sharper finite extinction time results for solutions of a class of damped nonlinear Schr{\"o}dinger equations when the nonlinear damping term corresponds to the limit cases of some ``saturating non-Kerr law'' $F(|u|^2)u=\frac{a}{\varepsilon+(|u|^2)^\alpha}u,$ with $a\in\mathbb{C},$ $\varepsilon\geqslant...
2111.10136v2
2022-01-26
Effect of Chiral Damping on the dynamics of chiral domain walls and skyrmions
Friction plays an essential role in most physical processes that we experience in our everyday life. Examples range from our ability to walk or swim, to setting boundaries of speed and fuel efficiency of moving vehicles. In magnetic systems, the displacement of chiral domain walls (DW) and skyrmions (SK) by Spin Orbit ...
2201.10742v1
2022-01-27
A Study on Monte Carlo simulation of the radiation environment above GeV at the DAMPE orbit
The Dark Matter Particle Explorer (DAMPE) has been undergoing a stable on-orbit operation for more than 6 years and acquired observation of over 11 billion events. And a better understanding of the overall radiation environment on the DAMPE orbit is crucial for both simulation data production and flight data analysis. ...
2201.11364v1
2022-05-10
Nonlinear damping quantification from phase-resonant tests under base excitation
The present work addresses the experimental identification of amplitude-dependent modal parameters (modal frequency, damping ratio, Fourier coefficients of periodic modal oscillation). Phase-resonant testing has emerged as an important method for this task, as it substantially reduces the amount of data required for th...
2205.04735v1
2022-06-08
Motion control with optimal nonlinear damping: from theory to experiment
Optimal nonlinear damping control was recently introduced for the second-order SISO systems, showing some advantages over a classical PD feedback controller. This paper summarizes the main theoretical developments and properties of the optimal nonlinear damping controller and demonstrates, for the first time, its pract...
2206.03802v2
2022-09-22
Neutrino Fast Flavor Pendulum. Part 2: Collisional Damping
In compact astrophysical objects, the neutrino density can be so high that neutrino-neutrino refraction can lead to fast flavor conversion of the kind $\nu_e \bar\nu_e \leftrightarrow \nu_x \bar\nu_x$ with $x=\mu,\tau$, depending on the neutrino angle distribution. Previously, we have shown that in a homogeneous, axisy...
2209.11235v3
2022-10-12
Second order two-species systems with nonlocal interactions: existence and large damping limits
We study the mathematical theory of second order systems with two species, arising in the dynamics of interacting particles subject to linear damping, to nonlocal forces and to external ones, and resulting into a nonlocal version of the compressible Euler system with linear damping. Our results are limited to the $1$ s...
2210.06162v1
2022-10-12
Stability of the Néel quantum critical point in the presence of Dirac fermions
We investigate the stability of the N\'eel quantum critical point of two-dimensional quantum antiferromagnets, described by a non-linear $\sigma$ model (NL$\sigma$M), in the presence of a Kondo coupling to $N_f$ flavours of two-component Dirac fermion fields. The long-wavelength order parameter fluctuations are subject...
2210.06577v3
2022-11-13
Damping analysis of Floating Offshore Wind Turbine (FOWT): a new control strategy reducing the platform vibrations
In this paper, the coupled dynamics of the floating platform and the WTG rotor is analysed. In particular, the damping is explicitly derived from the coupled equations of rotor and floating platform. The analysis of the damping leads to the study of the instability phenomena and it derives the explicit conditions that ...
2211.10362v1
2022-11-22
Universal Dynamics of Damped-Driven Systems: The Logistic Map as a Normal Form for Energy Balance
Damped-driven systems are ubiquitous in engineering and science. Despite the diversity of physical processes observed in a broad range of applications, the underlying instabilities observed in practice have a universal characterization which is determined by the overall gain and loss curves of a given system. The unive...
2211.11748v1
2023-01-23
Optimal Inter-area Oscillation Damping Control: A Transfer Deep Reinforcement Learning Approach with Switching Control Strategy
Wide-area damping control for inter-area oscillation (IAO) is critical to modern power systems. The recent breakthroughs in deep learning and the broad deployment of phasor measurement units (PMU) promote the development of datadriven IAO damping controllers. In this paper, the damping control of IAOs is modeled as a M...
2301.09321v1
2023-03-15
Blow-up and decay for a class of variable coefficient wave equation with nonlinear damping and logarithmic source
In this paper, we consider the long time behavior for the solution of a class of variable coefficient wave equation with nonlinear damping and logarithmic source. The existence and uniqueness of local weak solution can be obtained by using the Galerkin method and contraction mapping principle. However, the long time be...
2303.08629v1
2023-04-13
Centralised Multimode Power Oscillation Damping Controller for Photovoltaic Plants with Communication Delay Compensation
Low-frequency oscillations are an inherent phenomena in transmission networks and renewable energy plants should be configured to damp them. Commonly, a centralised controller is used in PV plants to coordinate PV generators via communication channels. However, the communication systems of PV plants introduce delays of...
2304.06415v1
2023-05-09
Glassy heat capacity from overdamped phasons and a hypothetical phason-induced superconductivity in incommensurate structures
Phasons are collective low-energy modes that appear in disparate condensed matter systems such as quasicrystals, incommensurate structures, fluctuating charge density waves, and Moir\'e superlattices. They share several similarities with acoustic phonon modes, but they are not protected by any exact translational symme...
2305.05407v2