LP-VIcode : A program to compute a suite of variational chaos indicators

Carpintero, D. D.; Maffione, N. P.; Darriba, Luciano Ariel

doi:10.1016/j.ascom.2014.04.001

Cited by 28 publications

(36 citation statements)

References 49 publications

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“…In the case of periodic orbits, it oscillates around a constant value (for further details we refer the reader to Fouchard et al 2002). From now on, we integrate the orbits and compute the preferred CI using the lp-vicode code (see Carpintero et al 2014). The numerical integrator conserves energy to an accuracy of one part in 10 −12 or less for all the experiments throughout the paper.…”

Section: Chaos Indicator: the Orthogonal Fast Lyapunov Indicatormentioning

confidence: 99%

On the relevance of chaos for halo stars in the solar neighbourhood II

Maffione

Gómez

Cincotta

et al. 2018

Monthly Notices of the Royal Astronomical Society

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In a previous paper based on dark matter only simulations we show that, in the approximation of an analytic and static potential describing the strongly triaxial and cuspy shape of Milky Way-sized haloes, diffusion due to chaotic mixing in the neighbourhood of the Sun does not efficiently erase phase space signatures of past accretion events. In this second paper we further explore the effect of chaotic mixing using multicomponent Galactic potential models and solar neighbourhood-like volumes extracted from fully cosmological hydrodynamic simulations, thus naturally accounting for the gravitational potential associated with baryonic components, such as the bulge and disc. Despite the strong change in the global Galactic potentials with respect to those obtained in dark matter only simulations, our results confirm that a large fraction of halo particles evolving on chaotic orbits exhibit their chaotic behaviour after periods of time significantly larger than a Hubble time. In addition, significant diffusion in phase space is not observed on those particles that do exhibit chaotic behaviour within a Hubble time.

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Section: Chaos Indicator: the Orthogonal Fast Lyapunov Indicatormentioning

confidence: 99%

On the relevance of chaos for halo stars in the solar neighbourhood II

Maffione

Gómez

Cincotta

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…When 10 −6 < SALI < 10 −8 we have the phenomenon of weak chaos where the corresponding orbits are irregular or not yet chaotic. For the computation of SALI we used the LP-VI code (Carpintero et al, 2014), a fully operational routine which efficiently computes a suite of many chaos indicators for dynamical systems in any number of dimensions.…”

Section: Methodsmentioning

confidence: 99%

Escape dynamics in a binary system of interacting galaxies

Zotos¹

2016

New Astronomy

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The escape dynamics in an analytical gravitational model which describes the motion of stars in a binary system of interacting dwarf spheroidal galaxies is investigated in detail. We conduct a numerical analysis distinguishing between regular and chaotic orbits as well as between trapped and escaping orbits, considering only unbounded motion for several energy levels. In order to distinguish safely and with certainty between ordered and chaotic motion, we apply the Smaller ALingment Index (SALI) method. It is of particular interest to locate the escape basins through the openings around the collinear Lagrangian points L 1 and L 2 and relate them with the corresponding spatial distribution of the escape times of the orbits. Our exploration takes place both in the configuration (x, y) and in the phase (x,ẋ) space in order to elucidate the escape process as well as the overall orbital properties of the galactic system. Our numerical analysis reveals the strong dependence of the properties of the considered escape basins with the total orbital energy, with a remarkable presence of fractal basin boundaries along all the escape regimes. It was also observed, that for energy levels close to the critical escape energy the escape rates of orbits are large, while for much higher values of energy most of the orbits have low escape periods or they escape immediately to infinity. We hope our outcomes to be useful for a further understanding of the escape mechanism in binary galaxy models.

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“…Therefore, if SALI ≤ 10 −7 the orbit is chaotic, while if SALI > 10 −7 the orbit is regular. For the computation of SALI we used the LP-VI code [17], a fully operational routine which efficiently computes a suite of many chaos indicators for dynamical systems in any number of dimensions.…”

Section: Methodsmentioning

confidence: 99%

Escapes in Hamiltonian systems with multiple exit channels: part II

Zotos

2015

Nonlinear Dyn

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We explore the escape dynamics in open Hamiltonian systems with multiple channels of escape continuing the work initiated in Part I. A thorough numerical investigation is conducted distinguishing between trapped (ordered and chaotic) and escaping orbits. The determination of the location of the basins of escape towards the different escape channels and their correlations with the corresponding escape periods of the orbits is undoubtedly an issue of paramount importance. We consider four different cases depending on the perturbation function which controls the number of escape channels on the configuration space. In every case, we computed extensive samples of orbits in both the configuration and the phase space by numerically integrating the equations of motion as well as the variational equations. It was found that in all examined cases regions of non-escaping motion coexist with several basins of escape. The larger escape periods have been measured for orbits with initial conditions in the vicinity of the fractal structure, while the lowest escape rates belong to orbits with initial conditions inside the basins of escape. In addition, we related the model potential with applications in the field of reactive multichannel scattering. We hope that our numerical analysis will be useful for a further understanding of the escape mechanism of orbits in open Hamiltonian systems with two degrees of freedom.

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LP-VIcode : A program to compute a suite of variational chaos indicators

Cited by 28 publications

References 49 publications

On the relevance of chaos for halo stars in the solar neighbourhood II

On the relevance of chaos for halo stars in the solar neighbourhood II

Escape dynamics in a binary system of interacting galaxies

Escapes in Hamiltonian systems with multiple exit channels: part II

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