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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:32 |
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Conference: Bucharest University Faculty of Physics 2007 Meeting
Section: Nuclear and Elementary Particles Physics
Title:
Numerical simulation of nucleon systems using a classical billiard model
Authors:
C. C. Bordeianu(1)(3), D. Felea(2), C. Besliu(1), Al. Jipa(1), I. V. Grossu(1)
Affiliation:
(1) University of Bucharest, Faculty of Physics, Bucharest-Magurele,PO Box MG 11, 077125, ROMANIA
(2)Institute of Space Sciences, Laboratory of Space Research,Bucharest-Magurele, PO Box MG 23, 076900, ROMANIA
(3)Technologic High School #1, Campulung Moldovenesc, Calea Transilvaniei 55, 725100, ROMANIA
E-mail
cristian.bordeianu@brahms.fizica.unibuc.ro
Keywords:
Lyapunov exponent; Kolmogorov-Sinai entropy; multifragmentation; power spectrum; autocorrelation; phase portrait
Abstract:
We consider several non interacting nucleons moving in a 2D Woods-Saxon type potential well and hitting the vibrating surface. The Hamiltonian has a coupling term between the particle motion and the collective coordinate which generatesa self consistent dynamics. The numerical simulation is based on the solutions of the Hamilton equations which was solved using an algorithm of Runge-Kutta type(order 4-5) having an optimized step size, taking into account that the absolute error for each variable is less than 10^−6. Total energy is conserved with high accuracy, i.e. approx. 10^−6 in absolute value. We analyze the chaotic behavior of the nonlinear dynamics system using phase-space maps, autocorrelation functions, power spectra,Lyapunov exponents and Kolmogorov-Sinai entropy.
In this frame we analyse the onset of dynamical behavior in different dynamical regimes prior to nuclear fragmentation. A qualitative and quantitative picture of the achievement of soft chaos is shown for a comparative study between different stages of the nuclear interaction.
Also we prove that the onset of nuclear fragmentation should be linked to the resonance stage of interaction.
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