scholarly journals The harder they fall, the bigger they become: tidal trapping of strings by microstate geometries

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Emil J. Martinec ◽  
Nicholas P. Warner
Keyword(s):  
Kinetic Energy ◽  
Transit Time ◽  
Incident Energy ◽  
Tidal Force ◽  
Massive String ◽  
Tidal Forces

Abstract We consider the fate of a massless (or ultra-relativistic massive) string probe propagating down the BTZ-like throat of a microstate geometry in the D1-D5 system. Far down the throat, the probe encounters large tidal forces that stretch and excite the string. The excitations are limited by the very short transit time through the region of large tidal force, leading to a controlled approximation to tidal stretching. We show that the amount of stretching is proportional to the incident energy, and that it robs the probe of the kinetic energy it would need to travel back up the throat. As a consequence, the probe is effectively trapped far down the throat and, through repeated return passes, scrambles into the ensemble of nearby microstates. We propose that this tidal trapping may lead to weak gravitational echoes.

Atomistic Mechanism of Ion Beam Deposition Induced Curvature Formation in Thin-Films

2007 ◽  
Author(s):  
Sachin S. Terdalkar ◽  
Sulin Zhang ◽  
Joseph J. Rencis
Keyword(s):  
Kinetic Energy ◽  
Incident Energy ◽  
Ion Beam ◽  
Md Simulations ◽  
Stress Generation ◽  
Intrinsic Stress ◽  
Graphene Sheets ◽  
High Incident Energy ◽  
Upward Deflection ◽  
Generation Mechanisms

Molecular dynamics (MD) simulations are performed to study the stress generation mechanisms in cantilever graphene sheets impacted by energetic carbon neutrals. The carbon-carbon interactions are described by the Tersoff-Brenner potential [1]. The MD simulations show that the free-end deflection of the graphene sheets is strongly dependent on the kinetic energy of the incident ions. At low incident energy (<<10eV), the free end bends towards to the side on which ions are deposited (upward deflection); at high incident energy, the free end bends away from the side on which the ions are deposited (downward deflection). The downward deflection reaches its maximum at around 50 eV, beyond which the downward deflection decreases with increasing incident energies. In addition, the evolution of the free-end deflection in terms of the number of deposited atoms is also dependent on the kinetic energy of the incident ions. These numerical observations suggest that intrinsic stress of different levels in the graphene sheets is generated. A close examination of the microstructures of the grown films indicates that the generated stress can be attributed to a competing mechanism of the production and annihilation of vacancy-like and interstitial-like defects in the films.

Neutral Beam Source Design and Beam Kinetic Energy Activated SiO2 Etching

1992 ◽  
Vol 279 ◽  
Author(s):  
Lee Chen ◽  
Akihisa Sekiguchi ◽  
Dragan Podlesnik
Keyword(s):  
Kinetic Energy ◽  
Chemical Reaction ◽  
Incident Energy ◽  
Beam Energy ◽  
Large Diameter ◽  
Low Energy ◽  
Neutral Beam ◽  
Beam Source ◽  
Neutral Radical ◽  
Unique Method

ABSTRACTAn unique method is used to produce a low energy nonthermalized fast neutral radical beam wliich can activate the SiO2 surface for chemical reaction at the desired incident energy. The fast neutral beam energy is continuously adjustable (2eV<Ek<200eV) and the beam flux is typically 5×1015cm−2 sec−1(∼4L). An uniform large diameter plasma is also made for the production of neutral beam covering 5”wafer and larger. Large diameter neutral beam single wafer reactor is feasible with off-the-shelf pumping technology.

scholarly journals Tidal forces in Kottler spacetimes

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
V. P. Vandeev ◽  
A. N. Semenova
Keyword(s):  
Black Hole ◽  
Cosmological Constant ◽  
Radial Component ◽  
Tidal Force ◽  
De Sitter ◽  
Geodesic Deviation ◽  
Tidal Forces ◽  
Sitter Spacetime ◽  
Deviation Equation ◽  
Deviation Vector

AbstractThe article considers tidal forces in the vicinity of the Kottler black hole. We find a solution of the geodesic deviation equation for radially falling bodies, which is determined by elliptic integrals. And also the asymptotic behavior of all spatial geodesic deviation vector components were found. We demonstrate that the radial component of the tidal force changes sign outside the single event horizon for any negative values of the cosmological constant, in contrast to the Schwarzschild black hole, where all the components of the tidal force are sign-constant. We also find the similarity between the Kottler black hole and the Reissner–Nordström black hole, because we indicate the value of the cosmological constant, which ensures the existence of two horizons of the black hole, between which the angular components of the tidal force change sign. It was possible to detect non-analytical behavior of geodesic deviation vector components in anti-de Sitter spacetime and to describe it locally.

Collision dynamics of cytosine under proton irradiation

2021 ◽  
pp. 2150242
Author(s):  
Chaoyi Qian ◽  
Zhiping Wang ◽  
Xuefen Xu ◽  
Yanbiao Wang ◽  
Fengshou Zhang
Keyword(s):  
Kinetic Energy ◽  
Incident Energy ◽  
Density Functional ◽  
Collision Dynamics ◽  
Electronic Density ◽  
Functional Theory ◽  
Scattering Angle ◽  
Valence Electrons ◽  
Damage Process ◽  
Incident Kinetic Energy

In the framework of the time-dependent density-functional theory, applied to valence electrons, coupled non-adiabatically to molecular dynamics of ions, the collision dynamics of cytosine impacted by proton is studied. We especially focus on the effect of the collision orientations on the damage of cytosine by choosing two collision orientations taking the oxygen atom on the double bond CO as the collision site with the incident energy of proton ranging from 150 eV to 1000 eV. First, two collision dynamical processes are explored by analyzing the molecular ionization, the ionic position and the kinetic energy, the energy loss of proton and the electronic density evolution. The results show that the damage process of cytosine induced by proton impact is mainly the capture of electrons by proton, the departments of ions and groups as well as the opening of ring. It is found that the orientation has little effect on the loss of the kinetic energy of proton, which is about 21.5[Formula: see text] of the incident energy of proton. Although the scattering angle [Formula: see text] has a polynomial relationship with [Formula: see text] in both cases, it is greatly affected by the orientation. When [Formula: see text] eV, the scattering angle of proton colliding with O along the x-axis is greater than that of proton colliding with O along the y-axis. The orientation also has a great effect on the mass distribution of the fragments and the fragmentation route. When proton moves along the x-axis, the fragmentation route is that O leaves the cytosine and the rest keeps on vibration, while products are not only related to the incident kinetic energy, but also show diversity when proton moves along the y-axis.

Simulation of the inner electrode geometry effect on the rundown phase characteristics of a coaxial plasma accelerator.

2021 ◽  
Vol 67 (1 Jan-Feb) ◽  
pp. 162
Author(s):  
C. Gómez Samaniego ◽  
M. Nieto Pérez ◽  
G. Ramos López
Keyword(s):  
Kinetic Energy ◽  
Electron Temperature ◽  
Plasma Density ◽  
Transit Time ◽  
Plasma Sheath ◽  
Electrode Geometry ◽  
Current Sheath ◽  
Conical Shape ◽  
Electrode Shape ◽  
Axial Acceleration

A 2D computational model, incorporating the Snowplow approximation in the mass balance, is used to simulate the acceleration of an annular current sheath along two coaxial electrodes, with the inner one having either cylindrical or conical shape. The circuit, mass and momentum equations are simultaneously solved in 2D (r, z) considering initial breakdown along the insulator surface, ideal gas mass accretion by the current sheath (snowplow model) and distributed inductance along a coaxial transmission line short-circuited by the current sheath. Plasma density and electron temperature in the current sheath are estimated using standard planar shock theory. Numerical integration of the model’s equations for a given electrode geometry yields the temporal evolution of the current sheath parameters during the axial acceleration phase. In order to see the effect of the inner electrode shape on sheath parameters (i.e. transit time, kinetic energy, total mass, shape, etc.) and/or circuit properties (i.e. circuit inductance, voltage and current evolution, etc.), the portion of the inner electrode beyond the insulator was given a conical shape. By changing the cone slant in a range between ±5°, it was found that the current driven on the plasma sheath varies nonlinearly with the angle. The divergent (positive angle) electrode gives the sheath the highest kinetic energy, being twice the value corresponding to that of the straight inner electrode case, and the transit time is reduced from 1.34 to 1.20 µs. The estimates of plasma density and electron temperature indicate that the achievable ion densities are on the order of 4x1022 m-3, which corresponds to 30 % ionization, and typical temperatures at the end of the rundown phase are on the order of 8 eV. These values are comparable with those measured in experimental devices. The development of this tool will enable us to benchmark its results against an experimental installation currently close to being operational, and a future follow-up paper will be devoted to the comparison between the prediction of the rundown phase behavior and experimental results utilizing conical electrodes.

scholarly journals Waves and tides in the atmosphere

1929 ◽  
Vol 126 (800) ◽  
pp. 169-183 ◽  
Keyword(s):  
Pressure Wave ◽  
Daily Variation ◽  
Barometric Pressure ◽  
Tidal Force ◽  
Periodic Oscillations ◽  
Tidal Forces ◽  
Waves And Tides ◽  
The Subject ◽  
Diurnal Effect ◽  
Chief Interest

Since the time of Laplace the periodic oscillations of the atmosphere as a whole have formed a constant subject for dynamical research. The chief interest has centred round the semidiurnal oscillation indicated by the great regularity of the semidiurnal component of the daily variation in barometric pressure. If the semidiurnal oscillation is due to gravitational tides it is very much greater than we should expect unless the tidal force is greatly enhanced by resonance. If it is due to the daily variation in temperature then should expect the diurnal effect to be greater than the semidiurnal unless the semidiurnal oscillation were greatly enhanced by resonance. Both these hypotheses involve the existence of a free period which differs from 12 hours by not more than 4 minutes. The inherent improbability that the appropriate mode of oscillation should chance to have a period so near to 12 hours caused Dr. H. Lamb to reject the tidal explanation of the semidiurnal pressure wave, but, as Prof. Chapman has pointed out in his very complete exposition of the subject, the “temperature variation” explanation requires resonance just as much as the “tidal” one. In fact Prof. Chapman attributes roughly half the effect to tidal forces and half to the daily variation in temperature.

scholarly journals Atmospheric Anomaly Analysis Related to Ms > 6.0 Earthquakes in China during 2020–2021

2021 ◽  
Vol 13 (20) ◽  
pp. 4052
Author(s):  
Xitong Xu ◽  
Shengbo Chen ◽  
Yan Yu ◽  
Sen Zhang
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Geopotential Height ◽  
Tectonic Stress ◽  
Tidal Force ◽  
Atmospheric Parameter ◽  
Mixing Ratio ◽  
Vertical Diffusion ◽  
Force Fluctuation ◽  
Tidal Forces

The attention towards links of atmospheric parameter variation and earthquakes has increased exponentially by utilizing new methods and more accurate observations. Persistent research makes it possible to gain insight into the precursor mechanism of earthquakes. In this paper, we studied the universality of detecting atmospheric anomalies associated with earthquakes based on tidal force fluctuation in China for earthquakes of Ms > 6.0, and explored the influence of tidal force on tectonic stress. The data of air temperature, geopotential height, ozone mixing ratio, and relative humidity from the National Center for Environmental Prediction (NCEP) were analyzed to reveal the spatiotemporal variation of atmospheric anomalies at multiple isobaric surfaces. Furthermore, the coupling of atmospheric parameters was investigated. The results showed that continuous solicitation exerted by tidal forces could change the strength of tectonic stress that causes earthquakes. The evolution pattern of air temperature, geopotential height, and relative humidity could be supported by atmospheric thermal vertical diffusion, while the anomalies of ozone mixing ratio was not evident. This verified the feasibility of detecting multi-parameter atmospheric anomalies associated with earthquakes based on tidal force fluctuation. Our results provide more evidence for understanding the atmospheric precursor characteristics of earthquakes.

scholarly journals Study on thermal anomalies of earthquake process by using tidal-force and outgoing-longwave-radiation

2018 ◽  
Vol 22 (2) ◽  
pp. 767-776 ◽  
Author(s):  
Xuedong Zhang ◽  
Chunli Kang ◽  
Weiyu Ma ◽  
Jing Ren ◽  
Yong Wang
Keyword(s):  
Outgoing Longwave Radiation ◽  
Regional Distribution ◽  
Maximum Amplitude ◽  
Longwave Radiation ◽  
Thermal Anomaly ◽  
Tectonic Stress ◽  
Rock Breaking ◽  
Tidal Force ◽  
Tidal Forces ◽  
Celestial Bodies

Four earthquakes above magnitude 5.0 in Yunnan and Tibet, China occurred from 2010 to 2011. By calculating the tidal-force changes induced by celestial bodies in this region, we found that the earthquakes occurred when tidal-forces continuous?ly grew from low to peak levels and approached the maximum amplitude phase, which indicated a tidal-force that had a trigger or inducing effect of active tectonic earthquakes when the ground stress reached a critical point. At the same time analyzing the abnormal changes of outgoing longwave radiation (OLR), along with the tidal cycle, indicated that the regional distribution of the enhancement region of OLR anomalies was closely related to geologic structure, especially ac?tive faults. The OLR radiation anomaly evolved: an initial infrared rise, followed by an enhancement reaching peak, attenuation, and then a return to normal. The entire process was similar to changes observed in rock-breaking process under stress loads. Our investigation showed that the tidal-force changes caused by ce?lestial bodies could trigger an earthquake when tectonic stress reached its critical breaking point, and the OLR anomaly was the radiation signature of the change in seismic tectonic stress. Therefore, the method of combining measurements of the tidal-force changes induced by celestial bodies with those of thermal-anomaly changes has some practical value for detecting the precursor state of impending earthquakes.

scholarly journals Tidal effects in 4D Einstein–Gauss–Bonnet black hole spacetime

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Jing Li ◽  
Songbai Chen ◽  
Jiliang Jing
Keyword(s):  
Black Hole ◽  
Initial Conditions ◽  
Tidal Force ◽  
Coupling Constant ◽  
Tidal Effects ◽  
Schwarzschild Spacetime ◽  
Geodesic Deviation ◽  
Tidal Forces ◽  
Black Hole Spacetime ◽  
Deviation Vector

AbstractWe have investigated tidal forces and geodesic deviation motion in the 4D-Einstein–Gauss–Bonnet spacetime. Our results show that tidal force and geodesic deviation motion depend sharply on the sign of Gauss–Bonnet coupling constant. Comparing with Schwarzschild spacetime, the strength of tidal force becomes stronger for the negative Gauss–Bonnet coupling constant, but is weaker for the positive one. Moreover, tidal force behaves like those in the Schwarzschild spacetime as the coupling constant is negative, and like those in Reissner–Nordström black hole as the constant is positive. We also present the change of geodesic deviation vector with Gauss–Bonnet coupling constant under two kinds of initial conditions.

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