Final Velocity Research Articles

Deep Structure of the Grenada Basin From Wide‐Angle Seismic, Bathymetric and Gravity Data

AbstractThe Grenada back‐arc basin is located between the Aves Ridge, which hosted the remnant Early Paleogene “Great Caribbean Arc,” and the Eocene to Present Lesser Antilles Arc. Several earlier studies have proposed different modes of back‐arc opening for this basin, including N‐S and E‐W directions. The main aim of this study is to constrain the circumstances leading to the opening of the basin. Three combined wide‐angle and reflection seismic profiles were acquired in the Grenada basin. The final velocity models from forward travel time and gravity modeling image variations in thickness and velocity structure of the sedimentary and crustal layers.The sedimentary cover has a variable thickness between 1 km on top of the ridges to ∼10 km in the basin. North of Guadeloupe Island, the crust is ∼20 km thick without significant changes between Aves Ridge, the Grenada basin, and the Eocene and present Lesser Antilles arc. South of Guadeloupe Island the Grenada basin is underlain by a oceanic crust of mainly magmatic origin over a width of ∼80 km. Here, the western flank of the Lesser Antilles Arc, the crust is 17.5‐km thick. The velocity structure of the Lesser Antilles Arc is typical of volcanic arcs or oceanic plateaus. West of the basin, the crust thickens to 25 km at Aves Ridge in an 80–100 km wide arc‐ocean transition zone. The narrowness of this transition zone suggests that opening might have proceeded in a direction oblique to the main convergence. Opening probably was accompanied by moderate volcanism.

Effects of Pre-Activation with Variable Intra-Repetition Resistance on Throwing Velocity in Female Handball Players: a Methodological Proposal.

The purpose of this study was to investigate the acute effect of pre-activation with Variable Intra-Repetition Resistance and isometry on the overhead throwing velocity in handball players. Fourteen female handball players took part in the study (age: 21.2 ± 2.7 years, experience: 10.9 ± 3.5 years). For Post-Activation Potentiation, two pre-activation methods were used: (I) Variable Intra-Repetition Resistance: 1 x 5 maximum repetitions at an initial velocity of 0.6 m·s-1 and a final velocity of 0.9 m·s-1; (II) Isometry: 1 x 5 s of maximum voluntary isometric contraction. Both methods were "standing unilateral bench presses" with the dominant arm, using a functional electromechanical dynamometer. The variable analysed was the mean of the three overhead throws. Ball velocity was measured with a radar (Stalker ATS). The statistical analysis was performed using ANOVA with repeated measures. No significant differences were found for either method (variable resistance intra-repetition: p = 0.194, isometry: p = 0.596). Regarding the individual responses, the analysis showed that 86% of the sample increased throwing velocity with the variable resistance intra-repetition method, while 93% of the sample increased throwing velocity with the isometric method. Both the variable intra-repetition resistance and isometric methods show improvements in ball velocity in female handball players. However, the authors recommend checking individual responses, since the results obtained were influenced by the short rest interval between the pre-activation and the experimental sets.

A Computational Study on the Detonation Velocity of Mixtures of Solid Explosives with Non‐Explosive Liquids

AbstractAccording to Urbanski's finding in a solid explosive with a density of less than the theoretical maximum density (TMD), the detonation velocity increases if the air contained in the explosive gets replaced by a non‐explosive liquid. In order to quantify this observation, the detonation velocities for RDX in combination with ten non‐explosive liquids were calculated using the EXPLO5 code (V6.05.04). It could be shown that pressing out the air of a high‐explosive powder and replacing the voids with a non‐explosive liquid such as ethylene glycol, water or glycerin helped to increase the final detonation velocity.

Experimental study of separation behavior of two bodies in hypersonic flow

The separation behavior of two bodies was experimentally investigated in a shock tunnel. Simple-shaped bodies, including a cylinder, cube, and sphere, with a size of 3 or 5 mm were used as the test models. The two contact models with a plane-exposed configuration were mounted using a thin wire, and the separation behavior was observed and analyzed using the shadowgraph technique. The surface roughness effect on the separation of two spheres was also considered. Particularly, attention was given to the lateral velocity. It was found that the spheres had a constant final lateral velocity after the shock interaction, whereas the velocities of the cylinders and cubes were determined by the rotational motion of the body. Based on the experimental data, a reentry trajectory analysis was conducted using Monte Carlo simulation. The results showed large ground footprint and downrange differences depending on the characteristics of the body, implying the importance of separation behavior for a reentry analysis.

Estimation of the Electrostatic Effects in the LISA-Pathfinder Critical Test Mass Dynamics via the Method of Moments

LISA-Pathfinder is an ESA space mission flown between 2015 and 2017 to demonstrate a technological maturity sufficient for building a gravitational waves telescope in space, such as the Laser Interferometer Space Antenna (LISA). A pair of cubic test masses is hosted inside the LISA-Pathfinder spacecraft and shielded from any force other than the interplanetary gravitational field. The purity of the shielding gives the performance of the mission. There are a number of aspects that had to be confirmed in-flight. One of them is the transition phase from the launch configuration, when the test masses are locked, to the science free-falling configuration. Each test mass is initially released from the mechanical constraints via a dedicated mechanism and then captured by an electrostatic control system. In fact, each test mass is surrounded by a set of electrodes for actuation and sensing purposes. The performance criterion of the release is the final velocity of the test mass relative to the spacecraft, with an upper threshold set to 5 $\mu m/s$. The LISA-Pathfinder first in-flight release velocities highlighted an unexpected dynamics with large linear and angular velocities. The electrostatic control was successful, but only relying on a manual procedure that cannot be considered as baseline for LISA. This paper helps investigating the in-flight non-compliance by dealing with the modeling of the electrostatic environment around each test mass and its contribution to the release and capture dynamics. The electrostatic model is based on the method of moments, a boundary element numerical technique suitable for estimating forces and capacitances between conductors. We also provide a short overview of the method, which can be used for the analysis of other phenomena within LISA and for the design of future gravitational waves telescopes and space projects.

Salmon oil supplementation in dogs affects the blood flow of testicular arteries

The administration of fish oils is known to cause changes in several reproductive parameters of domestic animals. The ingestion of polyunsaturated fatty acids (PUFAs) of the omega-3 family, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), has been described and correlated with changes in the semen quality, testosterone levels and male fertility. Nevertheless, few studies monitored and registered effects after ceasing supplementation. In the present study, we monitored the Doppler velocimetric and ultrasonographic parameters of nine dogs' testis for 90days (D90) checking the effect of salmon oil supplementation, and monitoring continued for 60days more, after ceasing supplementation (D150). Ultrasonographic evaluations comprised determining the Doppler velocimetric parameters, testicular and epididymal volume, and testicular echotexture. Peak systolic velocity (PSV) as well as final diastolic velocity (EDV) in the supratesticular arteries (STA), and marginal artery (MA) increased during the period of treatment and kept that level up to D150. There was no difference between the fish-oil supplementation period and the unsupplemented one regarding the testicular and epididymal volume and echogenicity and heterogeneity characteristics. A negative correlation was found between heterogeneity of testis and sperm production (r=-.41, p=.008). Doppler velocimetry indices were affected by the supplementation, leading to an increase in testicular blood flow.

Linear flow-velocity gradient chromatography-An efficient method for increasing the process efficiency of batch and continuous capture chromatography of proteins.

A new method was proposed for increasing the capture chromatography process efficiency, linear flow‐velocity gradient (LFG). The method uses a linear decreasing flow‐velocity gradient with time during the sample loading. The initial flow velocity, the final flow velocity and the gradient time are the parameters to be tuned. We have developed a method for determining these parameters by using the total column capacity and the total loaded amount as a function of time. The capacity can be calculated by using the relationships between dynamic binding capacity (DBC) and residence time. By leveraging the capacity, loading amount, and the required conditions, the optimum LFG can be designed. The method was verified by ion‐exchange and protein A chromatography of monoclonal antibodies (mAbs). A two‐fold increase in the productivity during the sample loading was possible by LFG compared with the constant flow‐velocity (CF) operation. LFG was also applied to a 4‐column continuous process. The simulation showed that the cost of resin per unit amount of processed mAbs can be reduced by 13% while 1.4 times enhancement in productivity was preserved after optimization by LFG compared to CF. The process efficiency improvement is more pronounced when the isotherm is highly favorable and the loading volume is large.

A Novel Proportional Navigation Based Method for Robotic Interception Planning With Final Velocity Control

This paper presents a new method for robot interception planning based on the proportional navigation. Guidance laws are basically developed for aerospace applications where a pursuer impacts a target using these methods, however in the robotic application it is required to have a smooth grasp between the robot and the goal. In this method, a new term is considered for longitude axis to have the control on the final approaching velocity. The proposed method not only ensures the position and velocity match (also referred to as rendezvous) but also can be used to set the final closing velocity to any desired value. Approaching velocity can be zero for grasping the goal or a specific known velocity for hitting it in a controlled manner. It is shown that the capture region of the proposed approach is wider that other proportional navigation based methods. The proposed method is implemented on Qbot-2 and its performance is experimentally validated.

Interaction between dual spherical particles during settling in fluid

Settling of solid particles in the fluid is one of the most basic forms of sediment transport. However, due to the complex particle–particle and particle–fluid interactions, the mechanism of settling is not yet fully understood. This study focuses on characterizing the dynamics of dual particles settling side by side. Both settling experiments and simulations are conducted with different initial spacings between particles and Reynolds numbers (Re). The range of Re is from 30 to 300, which corresponds to the transition zone between the Stokes and the Newton regime. Particle tracking velocimetry and particle image velocimetry are used in the experiments to determine particles’ trajectories and velocity fields around particles. A new electromagnetic release device is manufactured, which ensures accurate control of the initial condition. Together with the experiments, settling processes of particles are simulated based on discrete element–lattice Boltzmann method to investigate detailed flow structures. The results show that no attraction exists between particles when released simultaneously side by side. The repulsion between the two particles is a result of the asymmetry between the inside and outside vortices, and this repulsion will vanish when the initial spacing exceeds 5 particle diameters. Depending on the repulsion between particles, the settling process can be divided into three stages. The results also demonstrate that the initial spacing of the particles and Re are the two key parameters in the determination of the final settling velocity and separation distance. Their influence can be separated into two phase regimes depending on a critical Re (≈60), which is consistent with the one for the appearance of the Karman vortex street. In regime I (Re < 60), the settling process is dominated by viscous effects, and the effect of vortex interaction starts to take dominance in regime II (Re > 60). Overall, small initial spacing and large Re lead to strong repulsion between particles.

Equation-of-state measurements for polystyrene under high presure driven by HEAVEN-I laser facility

The equation of state (EOS) for CH material used as an ablator layer at high pressure is important in the study of implosion dynamics and target design for inertial confinement fusion (ICF). At present, most of EOS data are on the Hugoniot line under shock compression. The EOS data below Hugoniot line need further studying for low-entropy pre- compression. In the present article, the EOS of polystyrene is established under quasi-isentropic compression driven by HEAVEN-I KrF laser facility with a long rising edge (~20 ns). The shock dynamic behaviors of three kinds of CH targets are simulated, which are 100 μm CH planar target, Al-coated CH planar target (10 μm Al, 50 or 150 μm CH), and flyer-impact target composed of flyer (Al-coated CH), 100 μm vacuum layer, and 100 μm CH layer. The planar targets and flyer-impact targets with different thickness are irradiated by six-focused laser beams with total energy of 50–100J, and the free surface velocity and wave average transit velocity are measured by side-on shadowgraph technique. The simulation results indicate that the initial loading process is quasi-isentropic compression process, and then evolves into a weak shock compression process for the CH planar target in the rising edge stage. Comparing with the CH planar target, the reflected rarefaction waves from the Al-CH interface of Al-coated CH target can suppress the enhancement of compression wave, and delay the formation of shock wave when laser directly irradiates the Al layer. The shock pressure of the CH target layer (the third layer) is significantly higher than those of the former two targets in the flyer-impact target. However, the chasing rarefaction wave can unload the compression state incompletely and reduce the pressure when the CH target layer is much thicker than Al layer. The final pressure is about 15 GPa in the CH planar target, while the final pressure is about 30 GPa in flyer-impact target: both of them are less than the pressure threshold of opacity change for the transparent polystyrene. The quasi-isentropic dynamical process is difficult to measure by the velocity interferometer system for any reflector technique. The experimental results show that the average wave transit velocity is significantly less than the final shock velocity derived from the free surface velocities in the CH and Al-coated CH planar target side-on shadow experiments. They indicate that the compression wave enhancement and quasi-isentropic compression process occur in the propagation of wave front. The shock pressure is about 12 GPa in the CH planar target, and about 34 GPa under shock load in the flyer-impact target. The experimental data and shock dynamic processes are basically consistent with the simulation results.

Effect of abiotic stresses on germination behaviour of Ruta chalepensis

This work aims to highlight the optimal temperature for the seed germination of Ruta chalepensis, an important threatened ethnomedicinal shrub, and assess its germination tolerance against salinity and water stresses as well. For this, the seeds were incubated firstly under different temperatures (5 to 30°C). After that, at 20°C, germination tests were performed under different sodium chloride (NaCl) concentrations (0 to 273.9 mM) and various polyethylene glycol solutions (PEG6000) (0 to -2.20 bar). Final germination percentage, velocity coefficient and latency time were subsequently the germination patterns determined and analysed. The optimum temperature for germination was 15°C, in which the maximum final germination percentage (85%) was noticed; germination fell steadily, however, above and below this temperature and completely ceased at 30°C. Germination behaviour of R. chalepensis seeds under osmotic stress conditions showed a significant effect of both NaCl and PEG6000. Germination decreased whether sodium chloride or polyethylene glycol was increased in the medium (p < 0.05). Moreover, the salinity tolerance threshold was 205.4 mM, equivalent to 16 g L-1 NaCl, while water stress was -1.16 bar, corresponding to 80 g L-1 PEG6000. Beyond these thresholds, germination stopped. Dropping in velocity coefficient and postponing in latency time with increasing both stresses were recorded either. The sensitivity of R. chalepensis seeds to environmental stresses should be taken into account for successful conservation programmes, which should be implemented by sowing seeds and planting seedlings in fresh habitats with sufficient annual rainfall.

Efficient Approach for Atmospheric Phase Screen Mitigation in Time Series of Terrestrial Radar Interferometry Data Applied to Measure Glacier Velocity

The accuracy of surface displacements measured by differential radar interferometry is significantly degraded by the atmospheric phase screen (APS). This article presents a practical and efficient approach for APS mitigation based on the coherent pixels technique (CPT) displacement velocity estimation algorithm. In the proposed approach, all motionless coherent pixels closest to the moving area are defined as seeds surrounding the moving area at the integration step of the CPT. This arrangement consequently minimizes the integration path and the APS effect in the final velocity result. It is designed for terrestrial radar interferometry (TRI) applications. A piecewise processing chain is further introduced as a continuous operational mode processing framework to derive arbitrary temporal displacement patterns in this work. Three-day datasets measured by Ku-band TRI over a mountainous region in the canton of Valais, Switzerland, were used for validation. Through this validation, a comparative study of five algorithms was carried out. This evaluation showed the efficiency of the proposed approach. The proposed approach does not require phase unwrapping, kriging interpolation, and spatio-temporal covariance inference for APS mitigation, which is appropriate for continuous TRI operation.

МНОГОЛЕТНИЕ ИЗМЕНЕНИЯ ЛЕДОВИТОСТИ В РАЙОНЕ АРХИПЕЛАГОВ ШПИЦБЕРГЕН И ЗЕМЛЯ ФРАНЦА-ИОСИФА

A comparative analysis of inter-annual changes in ice coverage and time scales of its variability in the waters surrounding the Svalbard and Franz Josef Land archipelagos has been performed. The analysis was carried out for the selected quasi-homogeneous regions. Open sources of information (satellite observations) collected by the Arctic and Antarctic Research Institute were used. Seasonal and inter-annual changes in ice coverage were studied over the period 1979–2019, since the uniform series of the satellite data were available for this period. The change of a relatively stable type of ice regime to a regime with a high level of inter-annual variability, which occurred in 2004–2006, was established. A significant negative trend in the change in ice coverage, characteristic of the waters surrounding both archipelagos, was revealed. Correlation and spectral analyses were used to estimate possible periods of cyclic fluctuations in ice coverage (taking into account the limited duration of the observation series), which amounted about 5–6 years. An efforts were made to establish possible relationships between the ice coverage fluctuations and the main atmospheric and oceanic indices. Essentially, no statistical connection with the main atmospheric indices (Arctic and North Atlantic Oscillations) was found, but the feedback with the Atlantic Multi-decadal Oscillation index had been established. The maximum correlation coefficients for Spitsbergen are observed in the winter season, while in the area of Franz-Joseph Land this takes place in summer, which may be attributed to the final velocity of the Atlantic Multidecadal Oscillation signal.

Multipole-moment effects in ion-molecule reactions at low temperatures: part I - ion-dipole enhancement of the rate coefficients of the He+ + NH3 and He+ + ND3 reactions at collisional energies Ecoll/kB near 0 K.

The energy dependence of the rates of the reactions between He+ and ammonia (NY3, Y = {H,D}), forming NY2+, Y and He as well as NY+, Y2 and He, and the corresponding product branching ratios have been measured at low collision energies Ecoll between 0 and kB·40 K using a recently developed merged-beam technique [Allmendinger et al., ChemPhysChem, 2016, 17, 3596]. To avoid heating of the ions by stray electric fields, the reactions are observed within the large orbit of a highly excited Rydberg electron. A beam of He Rydberg atoms was merged with a supersonic beam of ammonia using a curved surface-electrode Rydberg–Stark deflector, which is also used for adjusting the final velocity of the He Rydberg atoms, and thus the collision energy. A collision-energy resolution of about 200 mK was reached at the lowest Ecoll values. The reaction rate coefficients exhibit a sharp increase at collision energies below ∼kB·5 K and pronounced deviations from Langevin-capture behaviour. The experimental results are interpreted in terms of an adiabatic capture model describing the rotational-state-dependent orientation of the ammonia molecules by the electric field of the He+ atom. The model faithfully describes the experimental observations and enables the identification of three classes of |JKMp〉 rotational states of the ammonia molecules showing different low-energy capture behaviour: (A) high-field-seeking states with |KM| ≥ 1 correlating to the lower component of the umbrella-motion tunnelling doublet at low fields. These states undergo a negative linear Stark shift, which leads to strongly enhanced rate coefficients; (B) high-field-seeking states subject to a quadratic Stark shift at low fields and which exhibit only weak rate enhancements; and (C) low-field-seeking states with |KM| ≥ 1. These states exhibit a positive Stark shift at low fields, which completely suppresses the reactions at low collision energies. Marked differences in the low-energy reactivity of NH3 and ND3—the rate enhancements in ND3 are more pronounced than in NH3—are quantitatively explained by the model. They result from the reduced magnitudes of the tunnelling splitting and rotational intervals in ND3 and the different occupations of the rotational levels in the supersonic beam caused by the different nuclear-spin statistical weights. Thermal capture rate constants are derived from the model for the temperature range between 0 and 10 K relevant for astrochemistry. Comparison of the calculated thermal capture rate coefficients with the absolute reaction rates measured above 27 K by Marquette et al. (Chem. Phys. Lett., 1985, 122, 431) suggests that only 40% of the close collisions are reactive.

Effect of End-Effector Compliance on Collisions in Robotic Teleoperation

In robotic teleoperation, hard impacts between a tool and the manipulated object may impair the success of a task. In order to develop a robotic system that is able to minimize the final velocity of an object after impact, a comprehensive approach is adopted in this work, and the effect on the impact of the parameters of the tool and of the robot is studied. Mass, contact stiffness and damping, robot compliance and control and tool compliance are taken into account. A mathematical model including the tool and the robot moving along the approach direction shows that, in most conditions, robot compliance is not enough to mitigate the impact. A mechanical decoupling between the inertia of the tool and the inertia of the robot is needed. An elastic system based on a bi-stable mechanism is developed and its validity is shown by means of numerical simulations.

Walker solution for a magnetic domain wall driven by spin-orbit torques

A domain-wall configuration and a current-injection scheme are proposed which ensure the satisfaction of the boundary condition of the dynamic Walker wall driven by the spin-orbit torques (SOTs). The analytic solutions of the wall are obtained in the whole region of current by the traveling-wave method. In the steady regime, the initial velocity mainly depends on the Slonczewski SOT. Meanwhile, the final steady velocity largely relies on the fieldlike one. The critical behavior of velocity is closely linked to the ratio of the fieldlike SOT parameter $\ensuremath{\beta}$ to the Gilbert damping constant $\ensuremath{\alpha}$. Reducing the difference between $\ensuremath{\beta}$ and $\ensuremath{\alpha}$, the Walker breakdown is postponed and the Walker velocity is enhanced. Additionally, by adjusting an applied magnetic field, $\ensuremath{\beta}$ can be measured by halting the wall. In the periodic regime, the wall propagates back and forth with an average velocity increasing almost linearly for high currents.

Accuracy Analysis of Point Velocities Determined by Different Software Packages and GNSS Measurement Processing Methods

The paper analyzes the geodynamic network of the City of Zagreb for periodic campaigns carried out from 2006 to 2009 which were processed by different software packages. The first computations and processing results were obtained by using the scientific software Gamit/Globk and indicate the ongoing tectonic activity of the area. In this paper, all calculations were performed by using the scientific software Bernese. Processing strategies and applied error models in the Gamit and Bernese solution are analyzed. The results of the previous analyses show the need to perform GNSS measurements at intervals of up to one year, which is necessary for understanding the mechanism of the structural frame of the wider Zagreb area. The research and analysis performed in this paper indicate certain uncertainties in determining the velocities from periodic one-year GNSS measurements. When periodic GNSS observations are analyzed at time intervals shorter than 2.5 years, annual signals can cause significant errors in determining point velocities. The accuracy of determining velocities between annual time intervals depends on a number of factors: noise level in GNSS measurements, measurement sessions quantity and applied computation strategies. Previously, the time series analysis of observations was a key procedure in the context of geodynamic and geokinematic research and the FODITS algorithm was used for the analysis. A noise analysis on the daily time series of coordinates was performed for the purpose of understanding all influences on geodynamic points. Moreover, a correlation between the time series of observations was determined in order to estimate the final velocity uncertainty error. The purpose of this paper is to demonstrate the applicability of the methods and procedures used to determine the coordinates and velocities of points that can be reliably used for geodynamic and geokinematic analyses and consequently, timely responses to various geophysical phenomena due to earthquakes or other natural phenomena.

Accelerating full waveform inversion through Adaptive Gradient Optimization methods and Dynamic Simultaneous Sources

Summary Full-Waveform Inversion (FWI) is a procedure based on the minimization of a misfit (or cost) function applied to the difference between synthetic waveforms and real seismic traces that derives high-resolution velocity models. This is achieved through the iterative adjustment of the velocity model and/or some other physical parameters of the Earth’s subsurface, which generally implies large computational effort. In order to minimize this cost function we explore the use of Adaptive Gradient Optimization (AGO), a variant of Stochastic Gradient Descent (SGD) methods, combining them with a dynamic simultaneous sources strategy that allow us to reduce the computational cost involved in this process. AGO methods are computationally efficient, have little memory requirements and have the capability of adapting the step-length according to the optimization process’ evolution. Since a precise calibration of the step-length is needed to ensure efficiency, the AGOs are well-suited for this task because they are able to adapt the step-length according to the optimization’s development. In this work, we propose a simple non-linear relationship that allows an adjustment of the step-length with respect to the frequencies used in the multiscale FWI, avoiding the line-search strategy’s high computational burden. Additionally, the application of this new step-length rule into the AGO methods with a dynamic simultaneous sources strategy, allow us to concurrently accelerate and significantly improve the FWI’s numerical performance and results. We compare the performance and final results of seven AGO methods, using two different FWI misfit functionals (based on L1 and L2 norms) applied to estimate the final velocity models of two benchmark acoustic models: the Marmousi and the Canadian overthrust BP velocity models.

Coulomb explosion imaging for gas-phase molecular structure determination: An ab initio trajectory simulation study.

Coulomb explosion velocity-map imaging is a new and potentially universal probe for gas-phase chemical dynamics studies, capable of yielding direct information on (time-evolving) molecular structure. The approach relies on a detailed understanding of the mapping between the initial atomic positions within the molecular structure of interest and the final velocities of the fragments formed via Coulomb explosion. Comprehensive on-the-fly ab initio trajectory studies of the Coulomb explosion dynamics are presented for two prototypical small molecules, formyl chloride and cis-1,2-dichloroethene, in order to explore conditions under which reliable structural information can be extracted from fragment velocity-map images. It is shown that for low parent ion charge states, the mapping from initial atomic positions to final fragment velocities is complex and very sensitive to the parent ion charge state as well as many other experimental and simulation parameters. For high-charge states, however, the mapping is much more straightforward and dominated by Coulombic interactions (moderated, if appropriate, by the requirements of overall spin conservation). This study proposes minimum requirements for the high-charge regime, highlights the need to work in this regime in order to obtain robust structural information from fragment velocity-map images, and suggests how quantitative structural information may be extracted from experimental data.

Exploring the Small Mass Ratio Binary Black Hole Merger via Zeno's Dichotomy Approach.

We perform a sequence of binary black hole simulations with increasingly small mass ratios, reaching to a 128:1 binary that displays 13 orbits before merger. Based on a detailed convergence study of the q=m_{1}/m_{2}=1/15 nonspinning case, we apply additional mesh refinement levels around the smaller hole horizon [30] to reach successively the q=1/32, q=1/64, and q=1/128 cases. Roughly a linear computational resources scaling with 1/q is observed on eight-nodes simulations. We compute the remnant properties of the merger: final mass, spin, and recoil velocity, finding precise consistency between horizon and radiation measures. We also compute the gravitational waveforms: their peak frequency, amplitude, and luminosity. We compare those values with predictions of the corresponding phenomenological formulas, reproducing the particle limit within 2%, and we then use the new results to improve their fitting coefficients.