A generic feature of systems with long-range interactions is the presence of quasistationary states with non-Gaussian single particle velocity distributions. For the case of the Hamiltonian mean-field model, we demonstrate that a maximum entropy principle applied to the associated Vlasov equation explains known features of such states for a wide range of initial conditions. We are able to repro...

The velocity mapping ion imaging method is applied to the ion-molecule reactions occurring between C(+) and NH(3). The velocity space images are collected over the relative collision energy range from 1.5 to 3.3 eV, allowing both product kinetic energy distributions and angular distributions to be obtained from the data. The charge transfer process appears to be direct, dominated by long-range ...

Thermal imaging cameras are powerful tools for measuring the temperature distributions on the surfaces of water bodies. The velocity distribution of a water surface can also be determined by recording the motion of the water surface temperature distribution with a thermal imaging camera and then applying particle image velocimetry (PIV) methods to sequential thermal images to obtain the velocit...

Details of the boron nitride (BN) sputtering process are of interest for diagnostics and modeling of Hall thruster erosion. This contribution presents velocity distributions of sputtered boron atoms from BN targets. Measurements were performed for normally incident argon ions at energies of 300, 800, and 1200 eV, and xenon ion at 1200 eV. The velocity distributions were found using laser induce...

In this letter we study the observed distributions of rotational velocity in a sample of more than 16,000 nearby F and G dwarf stars, magnitude complete and presenting high precision V sini measurements. We show that the velocity distributions cannot be fitted by a maxwellian. On the other hand, an analysis based on both Tsallis and Kaniadakis power-law statistics is by far the most appropriate...

In continuing our earlier research, we find the formulae needed to determine the arbitrary functions in the Lemâıtre-Tolman model when the evolution proceeds from a given initial velocity distribution to a final state that is determined either by a density distribution or by a velocity distribution. In each case the initial and final distributions uniquely determine the L-T model that evolves b...

The probability density functions ~PDFs! of the velocity and the velocity difference field induced by a distribution of a large number of discrete vortex elements are investigated numerically and analytically. Tails of PDFs of the velocity and velocity difference induced by a single vortex element are found. Treating velocities induced by different vortex elements as independent random variable...

The problem of ballistically controlled annihilation is revisited for general initial velocity distributions and an arbitrary dimension. An analytical derivation of the hierarchy equations obeyed by the reduced distributions is given, and a scaling analysis of the corresponding spatially homogeneous system is performed. This approach points to the relevance of the nonlinear Boltzmann equation f...