We perform analysis of the three-dimensional kinematics of Milky Way disk stars in mono-age populations. We focus on stars between Galactocentric distances of R = 6 and 14 kpc, selected from the combined LAMOST DR4 red clump giant stars and Gaia DR2 proper motion catalogue. We confirm the 3D asymmetrical motions of recent works, and we provide time tagging of the Galactic outer disk asymmetrical motions near the anticenter direction out to Galactocentric distances of 14 kpc. Radial Galactocentric motions reach values up to 10 km s −1 , depending on the age of the population, and present a north-south asymmetry in the region corresponding to density and velocity substructures that were sensitive to the perturbations in the early 6 Gyr. After that time, the disk stars of this structure are becoming older and kinematically hotter and not sensitive to the possible perturbations, and we find it is a low α, metal rich, relatively younger population. With the quantitative analysis, we find stars both above and below the plane at R 9 kpc exhibit bending mode motions of which the sensitive duration is around 8 Gyr. Some possible scenarios for these asymmetries are discussed, including a fast rotating bar, spiral arms, minor mergers, sub-halos, warp dynamics, and streams. Although we cannot rule out other factors, for the current results, we speculate that the in-plane asymmetries might be mainly caused by gravitational attraction of overdensities in a spiral arm or monolithic collapse of isolated self-gravitating overdensities from out-of-equilibrium systems. Vertical motions might be dominated by bending and breathing modes induced by inner or external perturbers.
The two-center atomic orbital close-coupling method is employed to study electron capture and excitation reactions in collisions of Liq+ (q = 1-3) ions with ground state atomic hydrogen in the ion energy range from 0.1 keV/u to 300 keV/u, where u is the atomic mass unit. The interaction of the active electron with the projectile ions (Li+, Li2+) is represented by a model potential. Total and state-selective cross sections for charge transfer and excitation processes are calculated and compared with data from other sources when available.
The toroidal plasma rotation braking effect during the application of n = 1 static resonant magnetic perturbation is studied by momentum transport analysis in the EAST tokamak. The braking torque shows a global profile and two peaks located near the plasma core and the edge, respectively. The effect of momentum diffusion contributes significantly to the calculated torque. Simulation results with the obtained torque and momentum diffusion coefficients well reproduce the observed plasma rotation evolution. Neoclassical toroidal viscosity (NTV) torque is modeled for comparison with the experimental torque. The total integrated NTV torque is around −0.12 Nm, which is comparable to the observed braking torque (around −0.33 Nm). In the plasma edge, there is a peak in the NTV torque profile, which agrees well in amplitude with the obvious peak in the observed torque density profile. An additional peak in the NTV torque profile due to the ion bounce resonance is also located in the core region. However, the magnitude of this peak is much smaller than the observed one near the plasma core.
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